
/*

  SmartClient Ajax RIA system
  Version v9.1p_2021-05-18/LGPL Deployment (2021-05-18)

  Copyright 2000 and beyond Isomorphic Software, Inc. All rights reserved.
  "SmartClient" is a trademark of Isomorphic Software, Inc.

  LICENSE NOTICE
     INSTALLATION OR USE OF THIS SOFTWARE INDICATES YOUR ACCEPTANCE OF
     ISOMORPHIC SOFTWARE LICENSE TERMS. If you have received this file
     without an accompanying Isomorphic Software license file, please
     contact licensing@isomorphic.com for details. Unauthorized copying and
     use of this software is a violation of international copyright law.

  DEVELOPMENT ONLY - DO NOT DEPLOY
     This software is provided for evaluation, training, and development
     purposes only. It may include supplementary components that are not
     licensed for deployment. The separate DEPLOY package for this release
     contains SmartClient components that are licensed for deployment.

  PROPRIETARY & PROTECTED MATERIAL
     This software contains proprietary materials that are protected by
     contract and intellectual property law. You are expressly prohibited
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*/
//>	@class	    ComboBoxItem
// The Combobox is a text input field which can show a list of options via a drop-down
// PickList.
// <p>
// The set of options will be filtered based on the current value in the text field, so only
// options that match what has been typed so far will be displayed.
// The set of options can be derived from a ValueMap or dynamically retrieved from a
// dataSource.  See the +link{interface:PickList} interface for further settings.
// <P>
// The two most common use cases for ComboBoxItems are:
// <ul><li>With +link{comboBoxItem.addUnknownValues} set to true, the ComboBoxItem acts as a
//  freeform text entry field with the picklist providing essentially a set of suggested completions
//  similar to a URL bar in a web browser.</li>
//     <li>With +link{comboBoxItem.addUnknownValues} set to false, the ComboBoxItem acts similarly
//  to a SelectItem where a fixed set of options is available to the user and the text entry field
//  is essentially used to filter which of these options are visible</li></ul>
// <P>
// Other commonly used settings to configure ComboBoxItem behavior are:<br>
// - +link{ComboBoxItem.defaultToFirstOption} - this will select the first option from the pickList
// as a default value for the item - and<br>
// - +link{ComboBoxItem.completeOnTab} which causes the
// current selection in the pickList (if there is one) to be chosen when the user tabs out of the
// field, allowing a user to type a few characters and hit tab to auto-complete to the first matched
// option. <code>completeOnTab</code> is automatically set to true if +link{comboBoxItem.addUnknownValues, addUnknownValues} is 
// false.
// <P>
// ComboBoxItem does not provide built-in support for multiple selection.  For a Combobox
// that does provide such a multiple-select feature use +link{MultiComboBoxItem}.
//
// @see interface:PickList
// @implements PickList
// @treeLocation Client Reference/Forms/Form Items
// @example listComboBox    
// @visibility comboBox
//<
// Example of a Combo-Box type item in Windows applications: The URL bar for most browsers.
// ComboBox is used for:
// - "search": ComboBox is in a search form which is bound to the DataSource being searched
//   - eg: autoCompletion on names in an address book
// - "find-related": ComboBox is in an editing form and is being used to pick related records
//   from other DataSources
//   - eg: when editing an Account, find a User record to use as account.owner
//   - in this case, we want to
//     - default to displaying identifying fields from the related records
//     - store the primary key of the related record, NOTE however:
//       - the fieldName in the record being edited may not be the same as the fieldName
//         of the PK in the related record
//       - we may not actually store the PK if field.foreignKey indicates some other field.
//         Eg, the primaryKey might be a meaningless internal value and we may store instead
//         some other unique value
isc.defineClass("ComboBoxItem", "TextItem", "PickList").addMethods({
    
    //>@attr ComboBoxItem.defaultValue (boolean : null : IRW)
    // Static default value for this ComboBoxItem. To default to the first option use
    // +link{ComboBoxItem.defaultToFirstOption} instead.
    // @visibility external
    //<
    
    //> @method ComboBoxItem.defaultDynamicValue() (A)
    // Expression evaluated to determine the +link{ComboBoxItem.defaultValue} when no value is 
    // provided for this item. To default to the first option use
    // +link{ComboBoxItem.defaultToFirstOption} instead.
    // @visibility external
    //<
    
    //> @attr ComboBoxItem.defaultToFirstOption (Boolean : false : IRW) 
    // Select the first option as the default value for this ComboBoxItem. If options are derived
    // from a dataSource, the first value returned by the server will be used, otherwise the first
    // value in the valueMap. If enabled, this setting overrides +link{ComboBoxItem.defaultValue}
    // and +link{ComboBoxItem.defaultDynamicValue}.
    // @visibility external
    //<
    
    //>@attr ComboBoxItem.showHintInField (boolean : null : IRWA)
    // If showing a hint for this form item, should it be shown within the field?
    // <P>CSS style for the hint is +link{selectItem.textBoxStyle} with the suffix
    // "Hint" appended to it. 
    // @group appearance
    // @see FormItem.hint
    // @visibility external
    //<

    //> @attr   comboBoxItem.mask  (string : null : IRWA)
    // Not applicable to a ComboBoxItem.
    // @visibility  external
    //<    
    //> @attr   comboBoxItem.maskSaveLiterals   (boolean : null : IRWA)
    // Not applicable to a ComboBoxItem.
    // @visibility  external
    //<    
    //> @attr   comboBoxItem.maskPadChar   (string : " " : IRWA)
    // Not applicable to a ComboBoxItem.
    // @visibility  external
    //<    
    //> @attr   comboBoxItem.maskPromptChar   (string : "_" : IRWA)
    // Not applicable to a ComboBoxItem.
    // @visibility  external
    //<    
    //> @attr   comboBoxItem.maskOverwriteMode   (boolean : null : IRWA)
    // Not applicable to a ComboBoxItem.
    // @visibility  external
    //<    
    
    // Default to auto-sizing pickList
    // This means the pickList will expand to the size required to accomodate its content.
    // As the user types and filters occur, this means the pickList may resize horizontally but
    // seems to have no obvious performance impact
    autoSizePickList:true,

    
    //>@attr ComboBoxItem.progressiveLoading (Boolean : true : IRW)
    // Indicates whether or not this ComboBoxItem will load its list of options 
    // +link{DataSource.progressiveLoading,progressively}.  This property is copied onto the
    // underlying +link{class:PickList}.
    // @see DataSource.progressiveLoading
	// @group progressiveLoading
    // @visibility external
    //<
    
    
    // Override drawn() - if this is a databound pickList we want to perform a filter before
    // the pickList itself ever gets shown.
    
    drawn : function (a,b,c,d) {
        this.invokeSuper(isc.ComboBoxItem, "drawn", a,b,c,d);
        if (this.autoFetchData && this._getOptionsFromDataSource()) {
            
            this.filterWithValue = false;        
            this.fetchData(null, null, true);
        }
    },

    //> @attr comboBoxItem.showPickerIcon (Boolean : true : IRW)
    // @include FormItem.showPickerIcon
    // @visibility external
    //<
    showPickerIcon:true,

    //> @attr comboBoxItem.pickerIconWidth (int : 15 : IRWA)
    // @include FormItem.pickerIconWidth
    // @visibility external
    //<
    pickerIconWidth:15,

    //> @attr comboBoxItem.pickerIconHeight (int : null : IRWA)
    // Don't specify an explicit height for the picker icon - instead have it size to match the
    // height of the combo box item.
    // @visibility external
    //<
    pickerIconHeight:null,

    // Have native and synthetic selects' text styling match
	textBoxStyle:"selectItemText",

    //> @attr comboBoxItem.pickerIconSrc (SCImgURL : "[SKIN]/DynamicForm/ComboBoxItem_PickButton_icon.gif" : IRWA)
    // @include FormItem.pickerIconSrc
    // @visibility external
    //<
    pickerIconSrc:"[SKIN]/DynamicForm/ComboBoxItem_PickButton_icon.gif",

    // Apply some default properties to the picker icon.
    pickerIconProperties:{
        // We don't want it to be imgOnly because we need click handling, but we don't want it
        // in the page's tab order
        tabIndex:-1,
        showOver:true
    },
    
    // override modalPickList - we don't want to take focus from the text item when the
    // pickList is shown.
    modalPickList:false,
    
    //> @attr ComboBoxItem.showPickListOnKeypress  (Boolean : true : IRW)
    // Should the list of options be displayed whenever the user types into the 
    // the combo-box textArea, or only when the user clicks on the pick button or uses the 
    // explicit <code>Alt+Arrow Down</code> key combination?
    // @visibility comboBox
    //<
    showPickListOnKeypress:true,
    
    //> @attr comboBoxItem.saveOnEnter (Boolean : true : IRW)
    // ComboBox items will submit their containing form on enter keypress 
    // if +link{DynamicForm.saveOnEnter,saveOnEnter} is true. Setting this property to
    // <code>false</code> will disable this behavior.
    // <P>
    // Note that if the drop down list of options (pickList) is visible an
    // <code>Enter</code> keypress is used to select a value from the available set of
    // options and will not automatically cause form submission.
    //
    // @visibility external
    //<
    // default implementation of formItem.shouldSaveOnEnter() returns this
    saveOnEnter: true,

    
    //> @attr ComboBoxItem.completeOnTab (boolean : null : IRW)
    // If true, when the pickList is showing, the user can select the current value by hitting
    // the <code>Tab</code> key.
    // <P>
    // Note that <code>completeOnTab</code> is not compatible with +link{formatOnBlur}
    // @visibility comboBox
    //<
    //completeOnTab:null,
    
    //> @attr ComboBoxItem.formatOnBlur (Boolean : false : IRW)
    // With <code>formatOnBlur</code> enabled, this item will format its value
    // according to any specified static +link{formItem.formatValue(),static formatter}
    // as long as the item does not have focus. Once the user puts focus into the item
    // the formatter will be removed. This provides a simply way for developers to
    // show a nicely formatted display value in a freeform text field, without the need
    // for an explicit +link{formItem.formatEditorValue()} 
    // and +link{formItem.parseEditorValue()} pair.
    // <P>
    // Note that this attribute is not compatible with +link{completeOnTab}
    // @visibility external
    //<
    
    
    // Implement pickListShown to set up a page level mousedown handler to hide the pickList.
    
    pickListShown : function () {
        if (this.pickList.isVisible()) {
            // Don't pass in the 'fire once' param - if the user clicks outside we'll clear the
            // click event in response to that click. If the user clicks on the pickList
            // (or it's scrollbar, for example) we want to continue listening for future clicks
            // outside.
            this._pageClickID = 
                this.ns.Page.setEvent("mouseDown", this, null, "_clickOutside");
        }
    },
    
    // If the user clicks on the page while the pickList is up, hide the pickList
    
    _clickOutside : function () {
        var pl = this.pickList;
        if (!pl || !pl.isVisible()) return;
        var target = isc.EH.lastEvent.target;
        // Special-cases:
        // - if the user showed the header of the PL and clicked on the header menu
        //   we don't want to dismiss the menu
        // - if the user showed the filter of the PL and clicked in the filter row
        //   we don't want to dismiss the menu
        // - if the user show the filter row of the PL, and clicked a pickList from a
        //   selectItem within that filter form we don't want to dismiss...
        if (!pl.contains(target, true) &&
            (!pl._cornerMenu || !pl._cornerMenu.contains(target, true)) &&
            (!pl.filterEditor || pl.filterEditor.getEditForm() != target)
           )
        {
            var hitInnerPickList = false;
            if (pl.filterEditor) {
                var innerPickLists = pl.filterEditor.getEditForm().getItems().getProperty("pickList");
                innerPickLists.addList(pl.filterEditor.getEditForm().getItems().getProperty("picker"));
                
                for (var i = 0; i < innerPickLists.length; i++) {
                    if (innerPickLists[i] && innerPickLists[i].contains(target)) {
                        hitInnerPickList = true;
                        break;
                    }
                }
            }
            if (!hitInnerPickList) {
//                this.logWarn("target:" + target);
                pl.hide();
            }
        }
        
        // What to do on mouseUp?
        // - If the click occurred over the pickerIcon we don't want to re-show in response to 
        //   the click that follows this mouseDown.
        // - If the click occurred over the PickList, (or its scrollbar), in IE native focus will
        //   be taken from the textbox, even though the scrollbar is non-focusable.
        //   Restore focus on mouse up so the user can continue typing / do arrow-key navigation
        //   from the textbox.
        if (!this._dismissOnMouseUp) {
            this._dismissOnMouseUp = 
              this.ns.Page.setEvent("mouseUp", this, isc.Page.FIRE_ONCE, "_dismissPickListClick");
        }
        // Note: if the user is dragging the scrollbar, we'll see a dragStop event, with no
        // mouseUp
        if (!this._refocusOnDragStop) {
            this._refocusOnDragStop = 
              this.ns.Page.setEvent("dragStop", this, isc.Page.FIRE_ONCE, "_refocusFromPLMouseUp");
        }
    },
    _dismissPickListClick : function () {
        // If the click happened over this item, cancel it. this will prevent the 
        // pickList from showing when it was hidden on a mousedown and the user clicks this item.
        if (this.form._getEventTargetItemInfo().item == this) {
            this.ns.Page.clearEvent("dragStop", this._refocusOnDragStop);
            // no need to clear the dismissOnMouseUp event since it's marked as FIRE_ONCE
            delete this._refocusOnDragStop;
            delete this._dismissOnMouseUp;
            return false;
        }
        this._refocusFromPLMouseUp(true);
    },
    
    _refocusFromPLMouseUp : function (fromClick) {
        // Only clear the event we're not responding to since the events are marked as FIRE_ONCE
        
        if (fromClick == true) {
            this.ns.Page.clearEvent("dragStop", this._refocusOnDragStop);
        } else {
            this.ns.Page.clearEvent("mouseUp", this._dismissOnMouseUp);
        }
        delete this._refocusOnDragStop;
        delete this._dismissOnMouseUp;
        
        if (this.pickList && this.pickList.isVisible() && 
            this.pickList.contains(isc.EH.getTarget())) 
        {            
            this.focusInItem();
        }
    },
    
    // Implement pickListHidden to clear the page level click event to hide the pickList, if
    // we haven't already.
    pickListHidden : function () {
        if (this._pageClickID) this.ns.Page.clearEvent("mouseDown", this._pageClickID);
        delete this._pageClickID;
        delete this._lastFilterValue;
    },
    
    // Override handkeKeyPress - as the user types, we want to re-filter the list.
    // Also proxy Arrow key presses to the PickList to navigate through options.
    // Behavior:
    // - We don't want the list showing if 
    //      - there are no matches
    //      - the textItem is empty
    // - Otherwise we want the list to show.
    _$ArrowUp:"Arrow_Up", _$ArrowDown:"Arrow_Down",
    _$PageUp:"Page_Up", _$PageDown:"Page_Down",
    _$Escape:"Escape", _$Enter:"Enter", _$Tab:"Tab",
    handleKeyPress : function () {
        if (!this.hasFocus || this.isReadOnly()) return this.Super("handleKeyPress", arguments);

        var keyName = isc.EH.lastEvent.keyName,
            pickList = this.pickList,
            pickListVisible = (pickList ? (pickList.isDrawn() && pickList.isVisible()) : false);            

        // deliver PageUp/Down to the body to cause scrolling
        if (pickListVisible && (keyName == this._$PageDown || keyName == this._$PageUp)) {
            return pickList.body.handleKeyPress(isc.EH.lastEvent);
        }
        
        var enteredValue = this.getEnteredValue(),
            value = this.getValue(),
            isEmpty = (!enteredValue || enteredValue == isc.emptyString);
        
        if (keyName == this._$ArrowDown && isc.EH.altKeyDown()) {
            // By default we hide the picklist whenever we get a keypress and the value is
            // empty (this is for the case where the user clears out the combobox text value).
            // Set a flag here to avoid hiding the combobox unless the value has subsequently
            // changed.
            this._shownWithValue = enteredValue;
            this._shownOnEmpty = isEmpty;
            
            this.filterWithValue = false;
            this.showPickList();
            return false;
        }

        // when addUnknownValues is false, we don't actually update the value unless the
        // user picks something from the pickList or takes focus from the field.
        // Allow an Escape keypress to reset the display value to match the underlying
        // data value again.
        if (keyName == this._$Escape && this.addUnknownValues == false) {
            var displayValue = this.getDisplayValue(value);
            if (isc.isAn.emptyString(displayValue) && this._getShowHintInField()) {
                this._showInFieldHint();
            } else {
                this.setElementValue(displayValue);
            }
        }

        // Should we complete (select the current item from the PickList) on Enter keypress?
        // - If addUnknownValues is true, always select the hilighted row in the pickList on 
        //   enter keypress (complete on enter)
        // - If addUnknownValues is false:
        //  - if the user has moved up or down the list using the arrow keys then hits enter,
        //    complete on enter
        //  - otherwise, if completeOnEnter (currently undocumented) is explicitly set, respect it
        
        //
        //  - otherwise complete on enter unless we're embedded in a search form and have
        //    an option dataSource set - in which case assume the user is actually trying to do
        //    a substring match and enter should kick off a search.
        var isEnter = keyName == this._$Enter,
            completeOnEnter = false;
        if (isEnter && pickListVisible) {
            if (this.addUnknownValues == false) completeOnEnter = true;
            else if (this._userNavigated) completeOnEnter = true;
            else if (this.completeOnEnter != null) completeOnEnter = this.completeOnEnter;
            else {
                completeOnEnter = !this.form.isSearchForm || 
                                  !this._getOptionsFromDataSource();
            }
        }
        
        var navigate = pickListVisible && (keyName == this._$ArrowDown || keyName == this._$ArrowUp);
        this._userNavigated = navigate;
        
        if (pickListVisible) {
            // pass navigation keys (arrows) through to the drop-down list
            // so the user can navigate through the selection
            if (navigate ||
                // also pass "Enter" up to the list to trigger 'itemClick' behavior
                // and "Escape" to trigger 'cancel' behavior
                (isEnter && completeOnEnter) || keyName == this._$Escape) 
            {
                pickList.bodyKeyPress(isc.EH.lastEvent);
                // kill the native behavior - shifting the cursor in the text field
                return false;
            }
            // hide the pickList on enter if completeOnEnter is false.
            
            if (isEnter) pickList.hide();
        }
        
        // We want to style "pending" values differently from actually chosen values
        // when addUnknownValues is false
        
        if (!this.addUnknownValues) this._markPending();

        return this.Super("handleKeyPress", arguments);
    },
    
    // check for Tab keypress (for completeOnTab) on keyDown rather than keypress
    // This is required for Safari where the focus shift to the next item occurs before
    // any Tab keypress event actually fires.
    shouldCompleteOnTab : function () {
        return this.completeOnTab || (this.addUnknownValues == false);
    },
    handleKeyDown : function () {
         if (!this.hasFocus || this.isReadOnly()) return this.Super("handleKeyDown", arguments);

        var keyName = isc.EH.lastEvent.keyName,
            pickList = this.pickList,
            pickListVisible = (pickList ? (pickList.isDrawn() && pickList.isVisible()) : false);            
        
        this._completeOnTabValue = null;
        
        // If completeOnTab is true, pick the currently selected value on tab.
        // Also do so if autoComplete:"smart" is enabled (inline autoCompletion),
        // as tab accepts an inline completion.
        if (keyName == this._$Tab && 
            (this.shouldCompleteOnTab() || this._getAutoCompleteSetting() == this._$smart)) 
        {
            // If we're currently pending a filter completion, wait for the filter to
            // complete before completing. Hang onto a 'completeOnTabValue' which we'll
            // check when the fetch completes.
            if (this._loadingData()) {
                this._completeOnTabValue = this.getEnteredValue();
            } else if (pickListVisible) {
                this._fireTabCompletion();
            }
        }
        
        return this.Super("handleKeyDown", arguments);
    },
    _loadingData : function () {
        return (this._queuedFetch || this._fetchingPickListData);
    },
    
    _fireTabCompletion : function () {
        var pickList = this.pickList;
        var selection = pickList.getSelectedRecord();
        if (selection != null) pickList.itemClick(selection);
        //this.logWarn("completing on keyDown, selection was: " + isc.echo(selection) +
        //             " value now: " + this.getValue());
    },
    
    // TextItem will call 'refreshDisplayValue' on blur to display the current data-value
    // remapped to display value.
    // This is intended to handle cases where there's a custom parser / formatter pair that
    // are not 1:1 [EG a forgiving date parser]. In this case a user may tab into a field,
    // modify the textual value to something that parses back to the underlying data value, then
    // tab out again and this method is responsible for displaying the formatted value again.
    // However -this interferes with our completeOnTab behavior since we would clobber the
    // user entered value and when the fetch completes _completeOnTabValue would no longer match
    // the result of 'getEnteredValue()'. -- therefore if we're currently
    // "_loadingData()" - IE performing asynchronous keypress handling or fetch - 
    // don't clobber the user-entered value.
    refreshDisplayValue : function () {
    return;
        if (this._loadingData()) return;
        
        if (this._pendingElementValue) return;
        return this.Super("refreshDisplayValue", arguments);
    },
    
    // Expose getEnteredValue() - commonly useful for pickLists
    //> @method comboBoxItem.getEnteredValue()
    // @include textItem.getEnteredValue()
    // @visibility external
    //<

    //> @attr comboBoxItem.addUnknownValues (Boolean : true : IRW)
    // This property controls whether the user can enter a value that is not present in the
    // set of options for this item.
    // <P>
    // If set to false, the value the user enters in the text box is essentially used to filter the 
    // set of options displayed in the pickList.
    // <P>
    // In this mode, when focus is taken from the field, if the entered value does not match
    // any entries in the +link{valueMap} or +link{optionDataSource}, it will be discarded. Note 
    // that in this mode, +link{comboBoxItem.completeOnTab} behavior is automatically enabled
    // so if the user enters a valid partial value such that one or more options is displayed in 
    // the pickList, and hits the Tab key, the first matching option will be chosen automatically.
    // In this mode the user may also hit the <code>"Escape"</code> key to discard their edits.
    // <P>
    // Note also that when <code>addUnknownValues</code> is set to false, the underlying value
    // returned by +link{formItem.getValue(),getValue()} will not be updated until a value is explicitly chosen. This
    // means any change or changed handlers will not fire directly in response to the user typing
    // in the field - they will fire when the user actually selects a value, or takes focus from 
    // the field.
    // <P>
    // If setting this property to <code>false</code> on a databound ComboBoxItem, data paging should
    // be disabled - this is required since the ComboBoxItem requires all data to be present in 
    // order to determine whether an entered value is new. Data Paging can be disabled by modifying
    // the +link{listGrid.dataFetchMode,dataFetchMode} on the +link{pickListProperties} for this
    // item.
    // <P>
    // If this property is set to true, the user is not limited to entering values present in
    // the set of options for the item. Instead the set of options essentially become a set of
    // suggestions that may be used, or the user can enter an entirely new value.
    // @visibility external
    //<
    // Notes: 
    // - If the valueMap is an object mapping data values to display values, or there
    //   is an optionDataSource specified with both display and value fields, should we allow
    //   the user to enter *data* values rather than display values?
    //   o if addUnknownValues is false, this is easy. We would ignore an entered value that
    //     didn't match a display value, even if it happened to be a data value.
    //     However it can be handled (if there's an optionDataSource) by
    //     setting the filterFields for the item to include the valueField - that way if the
    //     developer enters a data value, it'll show up in the pickList, and complete on tab.
    //   o if addUnknownValues is true this is less likely to be an issue since you'd be unlikely
    //     to be applying a valueMap on a field that supported freeform text entry. However we
    //     have to treat an entered value that doesn't match any display value as a data value of
    //     of course -- so if there is a matching data value in the valueMap already we would 
    //     select it. The trick is that we'll not update the item to show the display value
    //     until the user takes focus from the field. This is handled by logic in handleEditorExit()
    //     to call _checkForDisplayFieldValue() if necessary.
    
    
    addUnknownValues:true,
    
    //> @attr comboBoxItem.allowEmptyValue (Boolean : true : IRW)
    // If +link{comboBoxItem.addUnknownValues} is <code>false</code>, this property 
    // determines whether
    // the user can clear the comboBoxItem value, or whether they are constrained to
    // choosing one of the available options (in which case clearing the text box will
    // simply revert to the last picked value when the user leaves the field).
    // @visibility external
    //<
    allowEmptyValue:true,
    
    // Helper to determine if a user-entered value matches something in the 
    // pickList for this comboBoxItem. Note that the value passed in is the display value,
    // not the data value.
        
    isUnknownValue : function (value) {
        var vm = this.getValueMap();
        if (vm != null) {
            if (isc.isAn.Array(vm)) {
                if (vm.contains(value)) return false;
            
            } else if (isc.isAn.Object(vm)) {
                for (var key in vm) {
                    if (vm[key] == value) return false;
                }
            }
        }
        
        // At this point we didn't find the value in the valueMap - check for it
        // being present in the loaded optionDataSource data.
        var ODS = this.getOptionDataSource();
        if (ODS != null) {
            return this._translateValueFieldValue(value, true, true) == null;
        }
        return true;
    },
    
    // On editorExit:
    // - if addUnknownValues is false, check to see if we have a valid displayValue in our
    //   text box - if so, update our value (pick the appropriate explicitly entered option,
    //   or drop the value if there isn't one).
    //   - If we are currently fetching data for the pickList there are 2 exceptions here:
    //   1) User hit tab - in this case we will have set up _completeOnTabValue and when the
    //      fetch completes we'll auto-select the first option. Nothing else to do here
    //   2) User didn't hit tab but just took focus from the item. In this case we'll detect
    //      we don't have focus and check for the validity of the entered value on filterComplete,
    //      so again nothing to do here.
    //   Both these cases are ultimately handled by _updateValueForFilterComplete
    // 
    // - if addUnknownValues is true updateValue() should already have stored the appropriate 
    //   data value.
    //   If the value entered matched some entry in our pickList, and we have a displayField,
    //   we should have already mapped back to a data value and stored.
    //   Otherwise we have stored the entered value as a display value (User entered an "unknown"
    //   value).
    //   In this case, if we have both a displayField and a dataField, the
    //   entered value may be the data field value for some entry in our optionDataSource.
    //   This is a tricky case - we have to store the user-entered value as a data value
    //   so to keep it consistent with a call to 'setValue()' we should display the
    //   displayValue for the option if there is one.
    //   *We avoid this while focus is actually in the item to avoid changing user entered
    //    partial filter values etc.
    //   - call mapValueToDisplay to determine if we have a loaded entry where the entered value
    //     matches a data value, and if so display it.
    //   If not:
    //   1) We may have a pending fetch - allow _updateDisplayValueForNewData() to update the
    //   display value when the fetch completes
    //   2) Otherwise we need to kick off a new fetch to get the display value - in this case
    //   use "checkForDisplayFieldValue()" to kick off that new fetch.
    
    
    handleEditorExit : function () {
        // Assertion: all the logic below handles editor exit due to click outside, tab keypress and
        // essentially handles resolving the entered value to a live data value and displaying it
        // if necessary.
        // If the user actually clicked on the pickList we'll get an elementBlur ==> editorExit
        // on mouseDown, before itemClick has had a chance to fire.
        // Skip all this logic in that case.
        
        if (this._mouseDownInPickList()) return;
    
        // clear the _userNavigated flag used to determine whether to complete on enter keypress
        this._userNavigated = false;
    
        var elementValue = this.getEnteredValue(),
            value = this.getValue();
        
        if (this._completeOnTabValue != null && this._completeOnTabValue == elementValue &&
            !this._loadingData()) 
        {
            this._fireTabCompletion();
            this._completeOnTabValue = null;
            // re-fetch the elementValue - it should now be good if there was a valid completion
            elementValue = this.getEnteredValue();
        }
        
        // If completeOnTabValue is populated we're waiting for a fetch to complete to
        // update our value so skip logic to update value and/or displayed value on exit.
        if (this._completeOnTabValue == null) {
            if (this.addUnknownValues) {
            
                
                var ods = this.getOptionDataSource();
                if (value == elementValue && (ods == null || this.getDisplayFieldName != null)) {
                    if (value != null && this.shouldFetchMissingValue(value)) {
                        // _checkForDisplayFieldValue() will check whether we currently have a dataSource
                        // record for the value - if not it will kick off a fetch to retrieve such a value
                        // and update the display value when the fetch completes.
                        
                        this._checkForDisplayFieldValue(value);
                    }

                    // map the value passed to the visible value as necessary
                    var displayValue = this.mapValueToDisplay(value);
                    if (displayValue != value) {
                        if (isc.isAn.emptyString(displayValue) && this._getShowHintInField()) {
                            this._showInFieldHint();
                        } else {
                            this.setElementValue(displayValue);
                        }
                    }
                }
            } else {
                // If we're currently loading data wait for that to complete - otherwise
                // validate the entered value against our live pickList data and drop it
                // if its an "unknown" value now.
                if (!this._loadingData()) {
                    
                    // If the user entered something in the text box that actually matches
                    // a value in the pickList, update the data value. Otherwise reset to
                    // original value.
                    
                    if (this.isUnknownValue(elementValue)) {
                        this.setElementValue(this.getDisplayValue());
                    } else {
                       this._updateValue(elementValue, true);
                    }
                }
            }
        }
        // Don't validateOnExit if we're waiting on a complete-on-tab from an asynch fetch.
        this._suppressValidateOnEditorExit = (this._completeOnTabValue != null);
        var returnVal = this.Super("handleEditorExit", arguments);
        this._suppressValidateOnEditorExit = null;
        return returnVal;
    },
        
    // Reimplement/override _updateValueForFilterComplete()
    // If completeOnTab is true and the user hit tab mid-filter, we can complete now.
    // Also if addUnknownValues is false and focus was taken from the field mid
    // filter (without a tab keypress), accept or reject the typed value now.
    _updateValueForFilterComplete : function (response,data,request) {
    
        // Always select the default item at this point since we have the latest data
        this.selectDefaultItem();
        
        if (!this.hasFocus) {
            if (this._completeOnTabValue != null && 
                this._completeOnTabValue == this.getEnteredValue())
            {
                this._fireTabCompletion();
                this._completeOnTabValue = null;
            }
            // Check for 'unknown' value even if _completeOnTabValue was true.
            // We may have not returned any matches in which case _fireTabCompletion() would no-op
            // and we should now clear out the element value and restore any previously saved value
            if (!this.addUnknownValues) {
                var elementValue = this.getEnteredValue();
                if (this.isUnknownValue(elementValue)) {
                    var displayValue = this.getDisplayValue();
                    if (isc.isAn.emptyString(displayValue) && this._getShowHintInField()) {
                        this._showInFieldHint();
                    } else {
                        this.setElementValue(displayValue);
                    }
                    // Explicitly clear the "pending" flag
                    
                    this._markNotPending();
                } else {
                    // if there was a selected record before this filter ran, and it has the 
                    // same value and elementValue, just reselect the record
                    var r = this.getSelectedRecord();
                    if (r && r[this.valueField] == this._value && r[this.displayField] == elementValue) {
                         
                        this.pickList.selection.selectSingle(r);
                    } else {
                        this._updateValue(elementValue, true);
                        
                        elementValue = this.getEnteredValue();
                        if (this._getShowHintInField() &&
                            (elementValue == null || isc.is.emptyString(elementValue)))
                        {
                            this._showInFieldHint();
                        }
                    }
                }
            }
            
            // If validateOnExit is true, we suppressed it in handleEditorExit as we didn't
            // want to validate the partially entered value.
            // In this case, force validation now.
            this._performValidateOnEditorExit(this.getValue());
        }
        
        // call _updateDisplayValueForNewData()
        // This is overridden in PickList.js
        // For ComboBoxItems, if addUnknownValues is true, and we just loaded a record
        // for which the entered value is the display value, this method will call 
        // 'updateValue()' which will save out the relevant data value.
        // Otherwise this method will update the textbox to show the displayValue for the
        // item (standard behavior) iff the text box doesn't currently have focus - which
        // ensures we don't change the display value mid text-entry.
        this._updateDisplayValueForNewData();
    },
    
    //> @attr comboBoxItem.pendingTextBoxStyle (CSSStyleName : null : IRW)
    // Optional "pending" style for this item's text box.
    // <P>
    // If +link{comboBoxItem.addUnknownValues} is false, when the user modifies the
    // value displayed in the combobox item text box, the underlying data value (as returned
    // from item.getValue()) is not immediately updated - instead the value is used to filter
    // the set of results displayed in the comboBoxItem pickList.
    // <P>
    // While the comboBoxItem is in this pending state (where the result of getEnteredValue() will
    // not necessarily match the display value for whatever is returned by getValue()), the 
    // pendingTextBoxStyle may be applied to the text box for the item.
    // <P>
    // When the element value is updated to display the actual value for the item (typically due
    // to the user selecting a value from the pickList), the standard 
    // +link{TextItem.textBoxStyle} will be reapplied.
    // <P>
    // May be left unset in which case the standard text box style is always applied.
    // Has no effect if +link{addUnknownValues} is true.
    // @visibility external
    //<
    
    _markPending : function () {
        var wasPending = this._pendingElementValue;
        this._pendingElementValue = true;
        this._pendingEnteredValue = this.getEnteredValue();
        if (!wasPending) this.updateState();
    },
    _markNotPending : function () {
        if (!this._pendingElementValue) return;
        this._pendingElementValue = null;
        this._pendingEnteredValue = null;
        this.updateState();
    },
    getTextBoxStyle : function () {
        if (this.pendingTextBoxStyle == null || !this._pendingElementValue || this._isPrinting()) {
            if (this._isPrinting()) return isc.TextItem.getInstanceProperty("textBoxStyle");
            return this.Super("getTextBoxStyle", arguments);
        }
        return this.pendingTextBoxStyle;
    },
    
    _nativeCutPaste : function (element, item) {
        // set a flag indicating that the delayed update came from an IE-only native 
        // cut/paste - allows _updateValue() to show the pickList after a paste
        this._fromNativeCutPaste = true;
        this.Super("_nativeCutPaste", arguments);
    },

    // Override _updateValue()
    // If addUnknownValues is false, don't update the data value based on a change to the
    // text-box value unless the value was explicitly picked
    // from the pickList (this includes enter keypress, completeOnTab), or
    // focus is being taken from the item (in which case we pass in the forceSave param).
    _updateValue : function (value, forceSave) {

        // Clicking on the pickList first blurs the data element, causing
        // _updateValue() to be called. If the mouse is down in the pickList
        // then suppress the save.
        var mouseDownInPickList =  this._mouseDownInPickList(),
            suppressSave = (!forceSave &&
                                !this._valuePicked &&
                                (this.addUnknownValues == false || mouseDownInPickList));
        // If allowEmptyValue is true, and the user actually clears the text value,
        // actually save out the empty value, even if addUnknownValues is false.
        var updateFilterForEmptyValue = false;
        if (suppressSave && this.allowEmptyValue && (value == "")) {
            suppressSave = false;
            // If addUnknownValues is true, a user may enter a character, then
            // delete it.
            // in this case suppressSave will be marked true (due to this conditional), but
            // we'll compare against the stored value and avoid calling Super.
            // Catch this case and update the filter so the pickList doesn't continue to
            // reflect the filter for the character the user entered.
             if (!mouseDownInPickList) updateFilterForEmptyValue = true;
        }
        if (!suppressSave && !this._fromNativeCutPaste) {
            this._markNotPending();
            // Catch the case where we're already updated
            var dataValue = this.mapDisplayToValue(value);
            
            if (this._valuePicked) this.explicitChoice = this._valuePicked;
            
            if (this.compareValues(dataValue, this._value)) {
                if (updateFilterForEmptyValue) {
                    this.refreshPickList(value);                    
                }
                return true;
            }
            this.explicitChoice = this._valuePicked;

            return this.Super("_updateValue", arguments);
        
        // If addUnknownValues is false just refilter the pickList
        } else {
            // clear the flag that gets set in _nativeCutPaste() for IE
            if (this._fromNativeCutPaste) delete this._fromNativeCutPaste;

            
            if (this.changeOnKeypress && 
                this.length != null && isc.isA.String(value) && value.length > this.length) {
                value = value.substring(0, this.length);
                this.setElementValue(value);
            }
            

            // continue to filter the picklist based on the user-entered value
            
            if (this._mouseDownInPickList()) return;
            
            if (this._pendingElementValue == false) return;

            
            if (this._pendingEnteredValue != this.getElementValue()) {
                this._pendingEnteredValue = this.getElementValue();
            }

            
            if (this._pendingEnteredValue == this._lastFilterValue) return;

            this._lastFilterValue = this._pendingEnteredValue;
            this.refreshPickList(value);
        }
    },

    _minimalUpdateValue : function (newValue) {
        this.refreshPickList(newValue);
    },

    // Override handleChanged to re filter the list on every change (which occurs on every 
    // keypress that changed the entered value).  
    // Note handleChanged() is not called if addUnknownValues is false and the user
    // entered value has no completion - in that case, pickList refersh is triggered directly from
    // _updateValue()
    handleChanged : function (newValue, oldValue) {
        //this.logWarn("handleChange: newValue: " + newValue + " oldValue: " + oldValue);
        var returnVal = this.Super("handleChanged", arguments);
        this.refreshPickList(this.getEnteredValue());
        return returnVal;
    },
    // refresh the pickList for a change in the user-entered value
    // Note that newValue is a display value.
    refreshPickList : function (newValue) {
    
//         this.logWarn("refreshPickList called with newValue: " + newValue +
//                      ", valuePicked: " + this._valuePicked + this.getStackTrace());
        
        var isEmpty = (!newValue || newValue == isc.emptyString);
        
        // clear out the shownOnEmpty string if we're not empty any more. This means if
        // the user clicks the picker icon [pick list shows], then enters a character,
        // [pick list filters], then deletes that character, the pick list will hide
        if (!isEmpty) delete this._shownOnEmpty;

        // if the text field is empty, ensure the list is hidden unless it was explicitly
        // shown with an empty value (Arrow down keypress / picker click)
        var pickList = this.pickList,
            pickListVisible = (pickList ? pickList.isVisible() : false);
        if (isEmpty && !this._shownOnEmpty) {
            if (pickListVisible) pickList.hide();
        } else if (this.showPickListOnKeypress || pickListVisible) {
            // showPickList will set up the pickList initially, or if already set up
            // will re-filter
            // Note - if our value changed in response to the user picking something from the
            // list we don't want to show the pickList again.
            // Note - pass in the second 'queueFetches' parameter - we don't want to kick off
            // multiple server fetches while the user is rapidly typing in the text field
            
            if (!this._valuePicked && this.hasFocus) {
                
                if (!this.filterWithValue && (this._shownWithValue != newValue)) {
                    this.filterWithValue = true;
                    delete this._shownWithValue;
                }
                this.showPickList(true, true);
            }
        }
    },

    // Override selectDefaultItem to always select the first item in the list.
    // This will happen on every re-filter.
    selectDefaultItem : function () {    
        if (this.pickList == null || this.pickList.destroyed) return;
        
        var selection = this.pickList.selection;
        
        // If we have a record matching our value (or our pending, user-typed value)
        // select it as the default. This ensures that if the user hits tab or enter
        // we auto-complete correctly
            if (this.optionDataSource) {
            var record;
            
            if (!this.addUnknownValues && this._pendingEnteredValue != null) {
                record = this.getPickListRecordForValue(this._pendingEnteredValue)
            } else {
                record = this.getSelectedRecord();
            }

                if (record) {
                    this.pickList.clearLastHilite();
                    this.delayCall("selectItemFromValue", [record[this.valueField]]);
            return;
        }
        }

        // Otherwise select the first record in the list by default.
        var record = this.pickList.getRecord(0);
        // Don't attempt to select null / loading / separator rows
        if (record == null || Array.isLoading(record) || 
            record[this.pickList.isSeparatorProperty]) return;

        selection.selectSingle(record);
        // Clear last hilite - required so keyboard navigatioin will pick up the current position
        // from the selection, not the last hilite position.
        this.pickList.clearLastHilite();
        this.pickList.scrollRecordIntoView(0);
    },
    
    // Override getSelectedRecord to look at the pickList if present
    getSelectedRecord : function () {
          
        var record = this.Super("getSelectedRecord", arguments);
        
        // If we didn't get selected record via 'fetchMissingValues',
        // use the pickList to try to find the selectedRecord in the pickList data
        if (record == null && this._value != null && this.getOptionDataSource()) {
            record = this.getPickListRecordForValue(this._value);
            if (record != null) {
                // Store the record from the pickList in our displayField cache
                this._addDataToDisplayFieldCache([record]);
                this._updateSelectedRecord();
            }
        }
        return record;
    },
    
    // Given a value, reach into the pickList and find the associated record.
    getPickListRecordForValue : function (value) {
        var record;
            if (this.pickList == null || this.pickList.destroyed) {
                if (this.progressiveLoading === true || this.progressiveLoading === false) {
                    if (this.pickListProperties == null) this.picklistProperties = {};
                    this.picklistProperties.progressiveLoading = this.progressiveLoading;
                }
                this.makePickList(false);
            }
    
            if (this.pickList && this.pickList.data) {
            record = this.pickList.data.find(this.getValueFieldName(), value);
        }
        return record;
    },
    
    
    // ------------------------
    // Filtering data
    // ------------------------
    
    // Include useful JSDoc from pickList
    
    //> @attr ComboBoxItem.optionDataSource (DataSource | String : null : IRA)
    // @include PickList.optionDataSource
    //<
    
    //> @attr ComboBoxItem.pickListFields (Array of ListGridField : null : IRA)
    // @include PickList.pickListFields
    //<
    
    //> @method ComboBoxItem.fetchData()
    // @include PickList.fetchData()
    //<
    
    //> @attr comboBoxItem.cachePickListResults (boolean : true : IR)
    // For databound pickLists (see +link{pickList.optionDataSource}), by default SmartClient
    // will cache and re-use datasets shown by different pickLists displayed by different
    // SelectItems in an LRU (least recently used) caching pattern.
    // <P>
    // Setting this flag to false avoids this caching for situations where it is too
    // aggressive.
    // <p>
    // Note that this does not control re-use of data <b>within a single pickList</b>.  To
    // control when client-side filtering is used in ComboBoxItem, see
    // +link{ComboBoxItem.useClientFiltering} and +link{ComboBoxItem.filterLocally}.
    //
    // @visibility external
    //<
    
    //> @attr ComboBoxItem.fetchDisplayedFieldsOnly (boolean : null : IRA)
    // @include PickList.fetchDisplayedFieldsOnly
    //<
 
    //> @attr ComboBoxItem.optionFilterContext (DSRequest Properties : null : IRA)
    // @include PickList.optionFilterContext
    //<
 
    //> @attr ComboBoxItem.optionOperationId (string : null : [IR])
    // @include FormItem.optionOperationId
    // @visibility external
    //<
 
    
    //> @attr ComboBoxItem.displayField (string : null : IRWA)
    // @include PickList.displayField
    // @visibility external
    //<
    
    //> @attr ComboBoxItem.valueField   (string : null : IRW)
    // @include PickList.valueField
    // @visibility external
    //<
    
    //> @method ComboBoxItem.getDisplayFieldName() ([A])
    // @include PickList.getDisplayFieldName()
    // @visibility external
    //<
        
    //> @method ComboBoxItem.getValueFieldName()
    // @include PickList.getValueFieldName()
    // @visibility external
    //<
    
    //> @attr ComboBoxItem.filterLocally
    // @include PickList.filterLocally
    // @visibility external
    //<

    //> @method ComboBoxItem.getSelectedRecord()
    // @include FormItem.getSelectedRecord()
    // @visibility external
    //<
    
    //> @attr ComboBoxItem.pickListCriteria (Criteria : null : IRWA)
    // @include PickList.pickListCriteria
    // @visibility external
    //<
    
    //> @attr ComboBoxItem.showOptionsFromDataSource (boolean : null : IRWA)
    // @include PickList.showOptionsFromDataSource
    // @visibility external
    //<
    
    //> @attr ComboBoxItem.pickListProperties (ListGrid Properties : null : IRA)
    // @include PickList.pickListProperties
    // @visibility external
    //<

    //> @attr   ComboBoxItem.sortField   (String or integer : null : IR)
    // @include PickList.sortField
    // @visibility external
    //<

    
    // Default pickList interface 'filtering' basically returns every record (this is the
    // desired behavior for select items).
    // For pickLists we want to show only the subset of options that matches the string
    // currently in the combo box text element.

    // Set filterDisplayValues to ensure that if we're working with client side options,
    // the filter criteria are recognized as the display values for the data not the raw values.
    filterDisplayValue:true,
    
    //> @attr ComboBoxItem.autoFetchData   (Boolean : false : [IRA])
    // If this combo box retrieves its options from a <code>dataSource</code>, should options
    // be fetched from the server when the item is first written out, or should this fetch be
    // delayed until the user opens the pickList.
    //
    // @visibility external
    // @see PickList.optionDataSource
    //<
    autoFetchData:false,

    //> @attr ComboBoxItem.filterWithValue (Boolean : varies : [RA])
    // Read-only property set by the ComboBoxItem to indicate whether we should use the 
    // current typed-in value as part of the filter criteria returned by 
    // +link{ComboBoxItem.getPickListFilterCriteria()}.  You can check this flag in order to
    // mimic the ComboBoxItem's default behavior if you provide a custom implementation of
    // <code>getPickListFilterCriteria()</code>.
    // @see comboBoxItem.getPickListFilterCriteria()
    // @see comboBoxItem.filterFields
    // @visibility external
    //<
    
    //> @attr ComboBoxItem.alwaysFilterWithValue (boolean : false : [RA])
    // If set to true, the default implementation of 
    // +link{comboBoxItem.getPickListFilterCriteria()} will always add the current item's value
    // to any specified pickListFilterCriteria, regardless of the current value of 
    // +link{ComboBoxItem.filterWithValue}.
    // <P>
    // This was the default behavior for SmartClient version 5.6 and earlier.
    // @visibility internal
    //<
    
    //> @attr ComboBoxItem.filterFields (Array of String : null : IR)
    // As the user types into this item's textBox, a comboBoxItem will show the
    // pick-list of options, and filter the set of results displayed by the current value in the
    // text box. For a databound comboBoxItem, by default the entered value is filtered against
    // the +link{comboBoxItem.displayField,displayField} if one is specified, otherwise the
    // +link{comboBoxItem.valueField,valueField}.
    // <P>
    // This attribute allows the developer to explicitly change which fields to filter against,
    // causing the user-entered text to be matched against any of the specified set of fields from 
    // the +link{optionDataSource}.
    // <P>
    // This essentially causes +link{getPickListFilterCriteria()} to return an +link{AdvancedCriteria}
    // object representing "field1 starts with value or field2 starts with value or ...".  The
    // +link{OperatorId,operator} used is controlled by +link{textMatchStyle} as usual, that is,
    // "startsWith" implies the operator "iStartsWith, "substring" implies "iContains" and "exact"
    // implies "iEquals".
    // <P>
    // The most common use case for this setting would be when a comboBoxItem is showing multiple
    // +link{comboBoxItem.pickListFields} - if the same set of fields is specified as
    // +link{comboBoxItem.filterFields}, the user can use the text-box to filter against
    // whichever fields are visible in the pickList.
    // <P>
    // <smartclient>For finer grained control over comboBoxItem filtering, the 
    // +link{comboBoxItem.getPickListFilterCriteria()} method may be overridden.</smartclient>
    // <smartgwt>For finer grained control over comboBoxItem filtering, the
    // +link{comboBoxItem.setPickListFilterCriteriaFunction()} may be specified.</smartgwt>
    // @visibility external
    //<
    
    //> @groupDef comboBoxFiltering
    // The criteria used to decide which options should appear in
    // the drop-down +link{PickList} shown by a ComboBox are determined as follows.
    // <P>
    // While the user is typing in a value, the
    // +link{comboBoxItem.getPickListFilterCriteria()} method will return
    // the typed-in value as part
    // of the criteria, so that only matching values are shown.  Matching is determined by the
    // +link{comboBoxItem.textMatchStyle,textMatchStyle}.  Note that the +link{comboBoxItem.filterFields}
    // attribute may be used to determine which fields filtering is performed against for
    // databound comboBoxItems.
    // <P>
    // If the user explicitly shows the down-down pickList, via either clicking on the drop
    // down icon or using the <i>Ctrl+Arrow Down</i> key combination, the typed-in value is 
    // ignored for filtering.
    // <P>
    // If included in the criteria, the typed-in value will be included as a value for the 
    // +link{ComboBoxItem.displayField,displayField} (or for the
    // +link{ComboBoxItem.valueField,valueField} if <code>this.displayField</code> is
    // unspecified).
    // <P>
    // Static criteria, specified via +link{formItem.optionCriteria, optionCriteria} or
    // +link{comboBoxItem.pickListCriteria,pickListCriteria}, will always be included by the
    // default implementation (combined with the typed in value if appropriate).
    // <P>
    // <smartgwt>For custom pick list filter criteria, we recommend 
    // calling the 
    // {@link com.smartgwt.client.widgets.form.fields.ComboBoxItem#setPickListFilterCriteriaFunction}
    // method.</smartgwt>
    // <smartclient><code>getPickListFilterCriteria()</code> may be overridden for
    // custom behavior.</smartclient>
    // If you are implementing your own pickList filter criteria, the
    // <b>read-only</b> property +link{ComboBoxItem.filterWithValue,this.filterWithValue} can
    // be read to determine whether the ComboBox would ordinarily ignore the typed-in value for
    // filtering.  Note that in addition to cases where the user explicitly shows the pickList,
    // <code>filterWithValue</code> will also be <code>true</code> during a call to 
    // +link{ComboBoxItem.fetchData()} on a databound comboBox.
    // <P>
    // <b>NOTE:</b> The defaut implementation of this method will return an 
    // +link{AdvancedCriteria} object if multiple +link{comboBoxItem.filterFields} are specified, or
    // if there are field collisions between any specified static +link{formItem.optionCriteria, optionCriteria},
    // +link{comboBoxItem.pickListCriteria,pickListCriteria} and the entered value. AdvancedCriteria are not supported by
    // all DataSource types, including the built-in server-side SQL dataSources in SmartClient Pro
    // edition (though they are supported by SQL dataSources in Power and Enterprise editions).
    // <P>
    // <b>Client-Side Filtering</b><br>
    // By default, the ComboBoxItem will automatically use client-side filtering whenever
    // it receives a complete set of results for a given search string, and then the 
    // user types more letters (so reducing the results further).
    // <p>
    // Client-side filtering may malfunction if the server filtering behavior can't be 
    // replicated client-side (for example, Google Search).  To disable client-side 
    // filtering so that the comboBox always contacts the server for data whenever the 
    // use changes the search string, set +link{comboBoxItem.useClientFiltering} to false.
    // <p>
    // However, disabling client-side filtering will slow down the UI and cause more 
    // round-trips to the server, so if client-side filtering is malfunctioning but
    // <i>should work</i>, try to correct the problem rather than disable the feature.
    // <p>
    // For example, if the initial search works correctly but adding more letters
    // always causes zero matches, most likely the Records returned by the server lack
    // values for the field(s) targeted by the filter criteria, or the field values 
    // returned by the server don't match the criteria values. 
    // <P>
    // View the returned data in the RPC tab in the Developer Console and enable the
    // "ResultSet" log category in the "Results" tab to troubleshoot how the filter 
    // criteria are being applied to data, and look closely at your
    // settings for +link{comboBoxItem.valueField, valueField} and +link{comboBoxItem.displayField,displayField}.
    //
    // @title ComboBoxItem PickList Filtering
    // @visibility external
    //<
    
    //> @attr comboBoxItem.useClientFiltering (Boolean : null : IRA)
    // @include pickList.useClientFiltering
    // @visibility external
    //<
    
    //> @method  ComboBoxItem.getPickListFilterCriteria()    (A)
    // +link{group:stringMethods,StringMethod} to return filter criteria for options displayed for
    // this item.  
    // <P>
    // See +link{group:comboBoxFiltering} for details on how pickList filter criteria
    // are calculated by default for a comboBoxItem.
    //    
    // @return (Criteria) criteria to be used for databound or local filtering
    // @visibility external
    //<
    getPickListFilterOperator : function () {
        return (this.textMatchStyle == "startsWith" ? "iStartsWith" : 
                                  this.textMatchStyle == "exact" ? "iEquals" : "iContains")
    },
    getPickListFilterCriteria : function () {
        var crit = this.optionCriteria,
            pickListCriteria = this.pickListCriteria;
        
        if (pickListCriteria != null) {
            if (crit == null) crit = pickListCriteria;
            else {
                crit = isc.DataSource.combineCriteria(crit, pickListCriteria);
            }
        }
        if (this.alwaysFilterWithValue || this.filterWithValue) {
            // if filterFields are specified, explicitly use them.
            // Otherwise filter against the field that will actually be displayed
            // in the text box - this will be the displayField if specified, otherwise
            // the valueField.
            var filterFields = this.filterFields;
            if (filterFields == null) {
                filterFields = [this.getDisplayFieldName() || this.getValueFieldName()]
            }
            
            var value = this.getEnteredValue();
            var liveCrit;
            if (filterFields.length == 1) {
                liveCrit = {};
                liveCrit[filterFields[0]] = value;
                
            // Multiple fields: Build an advanced criteria object and do 'OR' 
            // matches to filter on each field passed in.
            } else {
                liveCrit = {
                    _constructor:"AdvancedCriteria",
                    operator:"or",
                    criteria:[]
                }
                for (var i = 0; i < filterFields.length; i++) {
                    liveCrit.criteria.add({
                        fieldName:filterFields[i],
                        value:value,
                        operator:this.getPickListFilterOperator()
                    });
                }
            }
            if (crit == null) crit = liveCrit;
            else crit = isc.DataSource.combineCriteria(crit, liveCrit);
        }
        
        return crit || {};
    },

    //> @attr ComboBoxItem.minimumSearchLength   (integer : null : [IRA])
    // Minimum length in characters before a search is performed. If too few characters
    // are entered the pick list shows +link{ComboBoxItem.searchStringTooShortMessage,
    // searchStringTooShortMessage}.
    //
    // @visibility external
    //<

    //> @attr ComboBoxItem.searchStringTooShortMessage   (String : "Enter a longer search string to search" : [IRA])
    // Message to display in pick list when +link{ComboBoxItem.minimumSearchLength,
    // minimumSearchLength} characters have not been entered.
    //
    // @visibility external
    //<
    searchStringTooShortMessage: "Enter a longer search string to search",

    isEntryTooShortToFilter : function () {
        var value = this.getEnteredValue();
        var tooShort = (value != null && value.length < this.minimumSearchLength);
        var result = ((this.filterWithValue || this.alwaysfilterWithValue) && tooShort);
        return result;
    },
    getEntryTooShortMessage : function () {
        return this.searchStringTooShortMessage;
    },
    // Never refresh for fetched value while focus is in our text box if the user has typed
    // If the user entered a display value we're already showing the right thing
    // If the user entered a data value, we'll remap to display on editor exit.
    _refreshForDisplayValueChange : function () {
        if (!this.hasFocus) return true;
        // Pending --> user has entered something that we haven't stored as this.value
        if (!this.addUnknownValues) return !this._pendingElementValue;
        
        // addUnknownValues:true - in this case we store out the value as the user types and
        // don't store a pending state. Use explicitChoice to determine whether the value was
        // set programmatically or picked from the list as opposed to just being typed.
        return !!this.explicitChoice;
    },
    

    //> @method comboBoxItem.getClientPickListData()
    // @include PickList.getClientPickListData()
    //<

    //> @method comboBoxItem.filterClientPickListData()
    // @include PickList.filterClientPickListData()
    //<

    //> @attr comboBoxItem.textMatchStyle (TextMatchStyle : "startsWith" : IR)
    // @include PickList.textMatchStyle
    //<

    //> @attr comboBoxItem.showAllOptions (boolean : null : IR)
    // @include PickList.showAllOptions
    //<
    
    //> @method ComboBoxItem.dataArrived()
    // @include PickList.dataArrived()
    // @visibility external
    //<

    //> @attr comboBoxItem.separatorRows (Array[] of ListGridRecord : [{isSeparator:true}] : IR)
    // @include PickList.separatorRows
    //<
    
    // When the user blurs from the combo box item we want to ensure we hide the pickList.
    
    elementBlur : function () {
        // note that handleEditorExit() / editorExit are called from super impl of elementBlur
        this.Super("elementBlur", arguments);
        
        
        if (isc.Browser.isMobile) {
            this.delayCall("hidePickListOnBlur", [true], 100);    
        } else {
            this.hidePickListOnBlur();
        }
    },
    hidePickListOnBlur : function (checkFocus) {

        
        delete this._lastFilterValue;

        if (checkFocus && ((this.hasFocus && this.containerWidget.hasFocus) || 
                            (this.pickList && this.pickList.body.hasFocus)) 
            )
        {
            return;
        }
        
        // if we show the header context menu we'll blur the native text item.
        // Don't hide the menu in response to this.
        if (this.pickList && this.pickList._showingHeaderContextMenu) return;

        var pickList = this.pickList,
            EH = isc.EH,
            event = EH.lastEvent;
        //this.logWarn("eventType is: " + event.eventType + 
        //             " event.target: " + event.target +
        //             " pickList.isAncestor: " + pickList.contains(event.target,true) +
        //             ", activeElement: " + this.echoLeaf(document.activeElement));

        // don't hide the pickList if it recieved the mouseDown event that tripped this blur.
        if (this._mouseDownInPickList() || 
                // ignore a delayed blur firing in IE when focus is still in the text input element
                (isc.Browser.isIE && this.getActiveElement() == this.getDataElement())
           ) 
        {
                return;
        }

        // ensure we don't show when 
        // - delayed filter is kicked off
        // - asynchronous filter completes
        delete this._showOnFilter;
        delete this._showOnDelayedFilter;

        // bail if the pickList isn't showing or has been passed to another form item already
        if (!pickList || !pickList.isVisible() || pickList.formItem != this) return;

        // hide the pickList
        pickList.hide();
    },
    _mouseDownInPickList : function () {
        var pickList = this.pickList;
        if (!pickList || !pickList.isVisible() || !pickList.isDrawn()) return false;
        var EH = isc.EH, event = isc.EH.lastEvent;
        if (   // the preceding event was a selectionChange event, which fires right after
               // mouseDown in the pickList, strangely triggered by some action we take in
               // Element._getElementFromSelection()
               // Special case because we can't look at event.target to determine if it was
               // a click on the pickList                   
               ( event.eventType == "selectionChange" && 
                 pickList.contains(isc.EH.mouseDownTarget()) )
               ||
    
               // it's a mouseDown/click on the pickList or one of it's subcomponents
               // have to specially check for click in a filter editor
               (
                (event.eventType == EH.MOUSE_DOWN || event.eventType == EH.CLICK ||
                // last event was a mouseMove and the mouse is still over the mouseDown target
                (event.eventType == EH.MOUSE_MOVE && EH.stillWithinMouseDownTarget())) &&
                (pickList.contains(event.target,true) || (pickList.filterEditor && pickList.filterEditor.getEditForm() == event.target)) 
               )
           )
        {
            return true;
        }
        return false;
    },

    editorEnter : function (form, item, value) {
        // Hide in-field hint if being shown
        this._hideInFieldHint();
    },
    editorExit : function (form, item, value) {
        var undef;
        if (this._completeOnTabValue == null && this._getShowHintInField() &&
            (value === undef || value == null || isc.is.emptyString(value)))
        {
            this._showInFieldHint();
        }
    },

    // Override showPicker to ensure we have focus, and show the pick list
    showPicker : function () {
        this.focusInItem();        
        
        this.filterWithValue = false;
        
        var value = this.getEnteredValue(),
            isEmpty = (!value || value == isc.emptyString);
        this._shownWithValue = value;
        this._shownOnEmpty = isEmpty;
        return this.showPickList();
    },    

    // pickValue
    // This method is fired when a value is selected from the pick list.
    // update the value of this item, and fire the change handler.
    pickValue : function (value) {

        // Make sure in-field hint is hidden
        this._hideInFieldHint();

        var displayValue = this.mapValueToDisplay(value);
        this.setElementValue(displayValue);
        // If we're focused, select the value so the user can single-click edit it.
        if (this.hasFocus) this.selectValue();
        
        // Hang a flag on the item so that we don't re-show the pick list
        this._valuePicked = true;
        this._pickedReverseValueMap = {};
        this._pickedReverseValueMap[displayValue] = value;
        // Note: updateValue() will fire change handlers and store the new data value.
        // The data value is derived back from the new display value via 'mapDisplayToValue()'
        
        this.updateValue();
        delete this._valuePicked;
    },

    // override setValue map to update the list and update the displayed value if necessary.
    setValueMap : function () {
        this.Super("setValueMap", arguments);
        if (this.pickList) {
            
            if (this.pickList.isVisible()) this.pickList.hide();
            
            // clear out the formItem property - ensures data / fields get re-set up when
            // the pickList is next shown.
            delete this.pickList.formItem
            // dont show the pickList if it's not already visible
            this.setUpPickList(this.pickList.isVisible());
        }
        // The display-version of the value is likely to have changed, so update the element
        // value at this point (but never update the typed-in value when addUnknownValues is
        // false)
        if (this.addUnknownValues) {
            var displayValue = this.getDisplayValue();
            if (isc.isAn.emptyString(displayValue) && this._getShowHintInField()) {
                this._showInFieldHint();
            } else {
                this.setElementValue(displayValue);
            }
        }
    },

    // Override setValue and mapValueToDisplay to ensure that on an explicit setValue() to
    // a value that's not currently loaded in the pickList dataSet, we show the display value
    // rather than the underlying data value.
    setValue : function (newValue, allowNullValue, partialValue,a,b) {
        // if setValue() is called on this item, but doesn't change the item value, 
        // and addUnknownValues is false, and we have
        // a pending value entered in our text box right now, reset to display the pending
        // value rather than the display value for the specified value.
        // This means if a form item is redrawn we won't drop the pending value the
        // user entered.
        
        var valueChanged = this._value != newValue;
        if (!valueChanged) {
            if (this._pendingElementValue && 
                (this._completeOnTabValue != null || this.hasFocus)) 
            {
                this.setElementValue(this._pendingEnteredValue);
                return;
            }
        }
        
        // clear the pending style
        this._markNotPending();
        
        this._programmaticSetValue = true;
        this.invokeSuper(isc.ComboBoxItem, "setValue", newValue, allowNullValue, partialValue, a, b);
        delete this._programmaticSetValue;

        // See if the in-field hint needs to be shown
        if (!this.hasFocus && this._getShowHintInField() && this.getHint()) {
            var undef;
            if (newValue === undef || newValue == null || isc.is.emptyString(newValue)) {
                this._showInFieldHint();
            }
        }
        // treat a call to setValue like the user picking a value from the form
        
        if (partialValue || newValue == null) {
            this.explicitChoice = false;
        } else if (valueChanged) {
            this.explicitChoice = true;
        }
    },
    
    // override getDefaultValue to support defaultToFirstOption
    // override getDefaultValue to pick up the first option if defaultToFirstOption is true
    // getDefaultValue should not be able to return a value that is not included
    // in the valueMap for this select.
    getDefaultValue : function () {
        
        var dV = this.Super("getDefaultValue", arguments);
        if (dV == null && this.defaultToFirstOption) {
            dV = this.getFirstOptionValue();
        }
        return dV;
    },
    
   
    
    // Overrides to logic to generate / parse criteria for use in search forms / filter editors
    // ---
    // If addUnknownValues is false and we have a displayField, and we are set to an "unknown"
    // value (IE we don't have a selected record), the most likely scenario is that the user
    // has entered a partial displayField value in the text box.
    // In this case use the displayField as the criteria fieldName and the pickList filter operator
    // as the search operator.
    // Also handle being passed criterion for the display field value and entering them in the
    // text box.
    
    
    //> @attr comboBoxItem.generateExactMatchCriteria (boolean : null : IRWA)
    // When a comboBoxItem is used to generate search criteria in a SearchForm this property
    // governs whether, if the user explicitly chose an option from the pickList, we explicitly
    // generate criteria that will search for an exact match against the chosen value.
    // <P>
    // In order to achieve this, when this property is set to true, this item will generate
    // +link{AdvancedCriteria} in <smartclient>its +link{getCriterion()} method</smartclient>
    // <smartgwt>the default <code>FormItemCriterionGetter</code>'s <code>getCriterion()</code>
    // method</smartgwt>.
    // <P>
    // See +link{shouldGenerateExactMatchCriteria()} for behavior when this flag is unset.
    // @visibility external
    //<
    
    //> @method comboBoxItem.shouldGenerateExactMatchCriteria() [A]
    // When a comboBoxItem is used to generate search criteria in a SearchForm, 
    // if the user explicitly chose an option from the pickList, should the criterion generated
    // by <smartclient>+link{getCriterion()}</smartclient>
    // <smartgwt>the <code>FormItemCriterionGetter</code>'s <code>getCriterion()</code> method</smartgwt>
    // enforce a search for an exact match against the chosen value?
    // <P>
    // In order to achieve this, when this property is set to true, this item will generate
    // +link{AdvancedCriteria} in <smartclient>its +link{getCriterion()}</smartclient>
    // <smartgwt>the default <code>FormItemCriterionGetter</code>'s <code>getCriterion()</code></smartgwt>
    // method.
    // <P>
    // Default implementation will return +link{generateExactMatchCriteria} if specified, otherwise
    // true if the DataSource for this item 
    // +link{DataSource.supportsAdvancedCriteria(),supports advanced criteria}, false if it
    // does not.
    // @return (Boolean) should getCriterion() generate exact-match search criteria when
    //   a value was explicitly chosen from this item's set of options?
    // @visibility external
    //<
    shouldGenerateExactMatchCriteria : function () {
        if (this.generateExactMatchCriteria != null) return this.generateExactMatchCriteria;
        var DS = this.form.getDataSource();
        
        if (DS && DS.supportsAdvancedCriteria()) return true;
        return false;
    },
    
    //> @method comboBoxItem.hasAdvancedCriteria()
    // Will this item return advancedCriteria if +link{DynamicForm.getValuesAsCriteria()} is 
    // called on this item's form?
    // Overridden for ComboBoxItem to return true if +link{generateExactMatchCriteria} is true
    // - in this case if an exact value is chosen from our set of options (always the
    // case if <code>addUnkownValues</code> is false), we will use advancedCriteria to ensure
    // the generated search criteria exactly matches the chosen value for this item.
    // <P>
    // Note that +link{AdvancedCriteria} are not supported by all dataSources. When a form is bound
    // to a dataSource, we therefore default <code>generateExactMatchCriteria</code> to false unless
    // the dataSource is known to support AdvancedCriteria.
    // <P>
    // As with formItem.hasAdvancedCriteria() this will also return true if a +link{operator}
    // was explicitly specified for this item
    // @return (Boolean) true if the result of getCriterion() will be an AdvancedCriteria object.
    // @group criteriaEditing
    // @visibility external
    //<
    // Desired behavior is really to have explicitly chosen values always do an exact match
    // against the value field, whereas partially entered values will do a partial match against
    // the display field (as they would with the pickList). For this to happen reliably we would
    // essentially always return advanced criteria - but AC are not supported by all dataSources
    // so we don't want this to be our default behavior.
    hasAdvancedCriteria : function () {
        if (this.Super("hasAdvancedCriteria", arguments)) return true;
        if (this.addUnknownValues && this.explicitChoice && this.shouldGenerateExactMatchCriteria())
            return true;
        return false;
    },
    //> @method comboBoxItem.getCriterion()
    // Returns criterion derived from the current value of this item.
    // <P>
    // If +link{addUnknownValues} is true for this item, we implement the following behavior.<br>
    // If the user explicitly selected an item from the pickList, we treat this as an attempt
    // to explicitly match the data value. In this case returned criteria will match the
    // selected (data) value against this item's fieldName.<br>
    // If the user typed a value into the text field, we treat this as an attempt to do a substring
    // type filter. In this case returned criteria will match the entered text value against the
    // displayField for this item if one is specified.
    // <P>
    // If +link{addUnknownValues} is false we always match the chosen data value against the item's 
    // fieldName.
    // <P>
    // Note that +link{shouldGenerateExactMatchCriteria()} will be called in the case when a
    // value was explicitly picked from the set of options. If that method returns true, we will
    // return AdvancedCriteria with an operator specified to ensure an exact match occurs.
    // 
    // @return (Criterion) criterion object based on this fields current edited value(s).
    // @group criteriaEditing
    // @visibility external
    //<
    getCriteriaFieldName : function () {
        if (this.criteriaField != null) return this.criteriaField;
    
        if (this.displayField != null && this.addUnknownValues && !this.explicitChoice) {
            return this.displayField;
        }

        // Explicit choice from pickList - return the valueField for the item.
        // Note: DO NOT CALL Super.getCriteriaFieldName() - we subclass TextItem which returns
        // displayField if set
        return this.getDataPath() || this.getFieldName();
    },
    
    //> @method comboBoxItem.getCriteriaValue()
    // Overridden to return the text box value if a displayField is specified for this item
    // and the user explicitly entered a display value in the text box field rather than
    // picking a specific value from the set of available options in the pickList.
    // @return (any) filter criterion value for this field
    //<
    getCriteriaValue : function () {
        if (this.displayField != null && this.addUnknownValues && 
            !this._showingLoadingDisplayValue &&
            !this.explicitChoice) 
        {
            return this.getEnteredValue();
        }
        return this.Super("getCriteriaValue", arguments);
    },

    getOperator : function (textMatchStyle) {
        var operator;
        // Note if addUnknownValues is false, return the filter operator if we're showing an
        // 'unknown' value, even if we don't have a displayField specified. In this case we
        // still want to do a substring match rather than an exact match.
        if (this.addUnknownValues && !this.explicitChoice) {
            operator = this.getPickListFilterOperator();
        } else {
            operator = this.Super("getOperator", arguments);
        }
        return operator;
    },
    
    //> @method comboBoxItem.canEditSimpleCriterion() [A]
    // Overridden to support editing simple criterion on the display field if one is specified
    // as well as the value field.
    // @return (boolean) true if this item can edit the specified fieldName
    //<
    canEditSimpleCriterion : function (fieldName) {
        if (this.getDataPath() && fieldName == this.getDataPath()) return true;
        if (this.criterionField) return fieldName == this.criterionField;
        if (this.displayField && fieldName == this.displayField) return true;
        return this.getFieldName() == fieldName;
    },
    
    // Override setSimpleCriterion - if the crit passed in is for the display field, we don't want
    // 'getCriterion()' to return a criterion on the data field.
    // Achieve this via the special "partialValue" param on setValue()
    setSimpleCriterion : function (value, fieldName) {
        if (this.criterionField == null && this.displayField != null && fieldName == this.displayField) {
            this.setValue(value, null, true);
        } else {
            this.setValue(value);
        }
    },

        
    //> @method comboBoxItem.canEditCriterion()
    // This method is overridden in comboBoxItem. When addUnknownValues is true, 
    // comboBoxItems allow the user to edit substring match type criteria applied to the
    // display field (if one is specified).
    // <P>
    // The user can also edit criteria attempting to match exactly against the item's field name.
    //
    // @group criteriaEditing
    // @visibility external
    //<
    canEditCriterion : function (criterion, warnOnField) {
        if (!this.addUnknownValues) {
            return this.Super("canEditCriterion", arguments);
        }
        
        if (this.getDataPath() && criterion.fieldName == this.getDataPath()) return true;

        var critField = criterion.fieldName,
            valueField = this.criterionField || this.getFieldName(),
            // We have to invoke super implementation of getOperator to pick up
            // our standard operator (typically just "equals" as we have an option dataSource)
            // as we override getOperator() to look at this.getSelectedRecord() which is
            // irrelevant to whether we can handle new criteria passed in.
            defaultOperator = this.Super("getOperator", []);
            
        if (critField != null) {
            if (this.displayField == null) {
                if (critField == valueField) {
                    return criterion.operator == defaultOperator
                            || criterion.operator == this.getPickListFilterOperator();
                }
            } else {
            
                if (critField == valueField) {
                    return criterion.operator == defaultOperator;
                } else if (critField == this.displayField) {
                    return criterion.operator == this.getPickListFilterOperator();
                }
            }
        }
        return false;
    },
    
    //> @method comboBoxItem.setCriterion()
    // Overridden to support editing criterion against the display field or value field when
    // +link{addUnknownValues} is true.
    // @group criteriaEditing
    // @visibility external
    //<
    setCriterion : function (criterion) {
        if (!this.addUnknownValues || this.displayField == null ||
            criterion.fieldName != this.displayField)
        {
            return this.Super("setCriterion", arguments);
        }
        
        // This is essentially setValue() but taking an explicit displayValue rather than
        // data value.
        var displayVal = criterion.value;
        this.setElementValue(displayVal);
        this._checkForDisplayFieldValue(displayVal);        
        var dataValue = this.mapDisplayToValue(displayVal);
        if (!this.compareValues(dataValue, this._value)) this.saveValue(dataValue);
    },
    
    // Override checkForDisplayFieldValue()
    // This is the method that, if we have a displayField specified, kicks off a fetch against
    // our optionDataSource to load the appropriate display value from the server.
    // In PickList based items we use the pickList data (if present) to map data to display 
    // values. 
    // Catch the case where checkForDisplayFieldValue is called when we are in the process of
    // fetching our pickList data from the server.
    // In this case we want to wait for the pickList data to be returned rather than kicking off
    // an additional fetch as our data value will usually be present in that pickList data.
    // When the pickList data returns we re-check this method. If the data is present, we're 
    // done, otherwise we need to kick off another fetch as we didn't find our data value in
    // the pickList data array. This can happen if the pickList data is paged, for instance.
    
    _checkForDisplayFieldValue : function (newValue, delayed) {
        var inValueMap = (this._mapKey(newValue, true) != null);
        
        if (inValueMap) {
            return; 
        }
        if (this._fetchingPickListData) {
            this._checkDisplayFieldValueOnFilterComplete = true;
            return;
        }
        // We can also bypass this if the pickList has a *complete* cache
        if (this.pickList != null && this.pickList.formItem == this && 
            isc.isA.ResultSet(this.pickList.data) && this.pickList.data.allRowsCached()) 
        {
            return;
        }
        this.invokeSuper(isc.ComboBoxItem, "_checkForDisplayFieldValue", newValue);
    },
    
    // Map valueToDisplay and mapDisplayToValue need to pick up
    // the mapping between displayField and valueField, if there is one.
    // We implement this by overriding _mapKey() / mapDisplayToValue() to check for the value in
    // our pickList's dataSet, in addition to checking against any explicitly specified valueMap
    
    
    _mapKey : function (value, dontReturnKey, a,b,c,d) {
        var displayValue = this.invokeSuper(isc.ComboBoxItem, "_mapKey", value, true ,a,b,c,d);

        // _translateFieldValue part of the pickList interface
        if (displayValue == null && this.getDisplayFieldName() != null) 
            displayValue = this._translateValueFieldValue(value, false);
        if (displayValue == null && !dontReturnKey) displayValue = value;            
        return displayValue;
    },

    
    mapDisplayToValue : function (value, a, b, c) {
        
        
        if (this._pickedReverseValueMap) {
            for (var i in this._pickedReverseValueMap) {
                if (i == value) {
                    return this._pickedReverseValueMap[i];
                }
            }
            delete this._pickedReverseValueMap;
        }
        if (this.getDisplayFieldName() != null) {
            var displayValue;
            displayValue = this._translateValueFieldValue(value, true);
            if (displayValue != null) value = displayValue;
        }
        return this.invokeSuper(isc.ComboBoxItem, "mapDisplayToValue", value, a,b,c);
    },

    _shouldAllowExpressions : function () {
        return false;
    },

    setReadOnlyDisplay : function (appearance) {
        this.Super("setReadOnlyDisplay", arguments);
    }
});


isc.ComboBoxItem.registerStringMethods({
    dataArrived:"startRow,endRow,data",
    getPickListFilterCriteria:""
});
