The source code

    /**
     * @class Ext.form.ComboBox
     * @extends Ext.form.TriggerField
     * <p>A combobox control with support for autocomplete, remote-loading, paging and many other features.</p>
     * <p>A ComboBox works in a similar manner to a traditional HTML &lt;select> field. The difference is
     * that to submit the {@link #valueField}, you must specify a {@link #hiddenName} to create a hidden input
     * field to hold the value of the valueField. The <i>{@link #displayField}</i> is shown in the text field
     * which is named according to the {@link #name}.</p>
     * <p><b><u>Events</u></b></p>
     * <p>To do something when something in ComboBox is selected, configure the select event:<pre><code>
    var cb = new Ext.form.ComboBox({
        // all of your config options
        listeners:{
             scope: yourScope,
             'select': yourFunction
        }
    });

    // Alternatively, you can assign events after the object is created:
    var cb = new Ext.form.ComboBox(yourOptions);
    cb.on('select', yourFunction, yourScope);
     * </code></pre></p>
     *
     * <p><b><u>ComboBox in Grid</u></b></p>
     * <p>If using a ComboBox in an {@link Ext.grid.EditorGridPanel Editor Grid} a {@link Ext.grid.Column#renderer renderer}
     * will be needed to show the displayField when the editor is not active.  Set up the renderer manually, or implement
     * a reusable render, for example:<pre><code>
    // create reusable renderer
    Ext.util.Format.comboRenderer = function(combo){
        return function(value){
            var record = combo.findRecord(combo.{@link #valueField}, value);
            return record ? record.get(combo.{@link #displayField}) : combo.{@link #valueNotFoundText};
        }
    }

    // create the combo instance
    var combo = new Ext.form.ComboBox({
        {@link #typeAhead}: true,
        {@link #triggerAction}: 'all',
        {@link #lazyRender}:true,
        {@link #mode}: 'local',
        {@link #store}: new Ext.data.ArrayStore({
            id: 0,
            fields: [
                'myId',
                'displayText'
            ],
            data: [[1, 'item1'], [2, 'item2']]
        }),
        {@link #valueField}: 'myId',
        {@link #displayField}: 'displayText'
    });

    // snippet of column model used within grid
    var cm = new Ext.grid.ColumnModel([{
           ...
        },{
           header: "Some Header",
           dataIndex: 'whatever',
           width: 130,
           editor: combo, // specify reference to combo instance
           renderer: Ext.util.Format.comboRenderer(combo) // pass combo instance to reusable renderer
        },
        ...
    ]);
     * </code></pre></p>
     *
     * <p><b><u>Filtering</u></b></p>
     * <p>A ComboBox {@link #doQuery uses filtering itself}, for information about filtering the ComboBox
     * store manually see <tt>{@link #lastQuery}</tt>.</p>
     * @constructor
     * Create a new ComboBox.
     * @param {Object} config Configuration options
     * @xtype combo
     */
    Ext.form.ComboBox = Ext.extend(Ext.form.TriggerField, {
        /**
         * @cfg {Mixed} transform The id, DOM node or element of an existing HTML SELECT to convert to a ComboBox.
         * Note that if you specify this and the combo is going to be in an {@link Ext.form.BasicForm} or
         * {@link Ext.form.FormPanel}, you must also set <tt>{@link #lazyRender} = true</tt>.
         */
        /**
         * @cfg {Boolean} lazyRender <tt>true</tt> to prevent the ComboBox from rendering until requested
         * (should always be used when rendering into an {@link Ext.Editor} (e.g. {@link Ext.grid.EditorGridPanel Grids}),
         * defaults to <tt>false</tt>).
         */
        /**
         * @cfg {String/Object} autoCreate <p>A {@link Ext.DomHelper DomHelper} element spec, or <tt>true</tt> for a default
         * element spec. Used to create the {@link Ext.Component#getEl Element} which will encapsulate this Component.
         * See <tt>{@link Ext.Component#autoEl autoEl}</tt> for details.  Defaults to:</p>
         * <pre><code>{tag: "input", type: "text", size: "24", autocomplete: "off"}</code></pre>
         */
        /**
         * @cfg {Ext.data.Store/Array} store The data source to which this combo is bound (defaults to <tt>undefined</tt>).
         * Acceptable values for this property are:
         * <div class="mdetail-params"><ul>
         * <li><b>any {@link Ext.data.Store Store} subclass</b></li>
         * <li><b>an Array</b> : Arrays will be converted to a {@link Ext.data.ArrayStore} internally,
         * automatically generating {@link Ext.data.Field#name field names} to work with all data components.
         * <div class="mdetail-params"><ul>
         * <li><b>1-dimensional array</b> : (e.g., <tt>['Foo','Bar']</tt>)<div class="sub-desc">
         * A 1-dimensional array will automatically be expanded (each array item will be used for both the combo
         * {@link #valueField} and {@link #displayField})</div></li>
         * <li><b>2-dimensional array</b> : (e.g., <tt>[['f','Foo'],['b','Bar']]</tt>)<div class="sub-desc">
         * For a multi-dimensional array, the value in index 0 of each item will be assumed to be the combo
         * {@link #valueField}, while the value at index 1 is assumed to be the combo {@link #displayField}.
         * </div></li></ul></div></li></ul></div>
         * <p>See also <tt>{@link #mode}</tt>.</p>
         */
        /**
         * @cfg {String} title If supplied, a header element is created containing this text and added into the top of
         * the dropdown list (defaults to undefined, with no header element)
         */

        // private
        defaultAutoCreate : {tag: "input", type: "text", size: "24", autocomplete: "off"},
        /**
         * @cfg {Number} listWidth The width (used as a parameter to {@link Ext.Element#setWidth}) of the dropdown
         * list (defaults to the width of the ComboBox field).  See also <tt>{@link #minListWidth}</tt>
         */
        /**
         * @cfg {String} displayField The underlying {@link Ext.data.Field#name data field name} to bind to this
         * ComboBox (defaults to undefined if <tt>{@link #mode} = 'remote'</tt> or <tt>'field1'</tt> if
         * {@link #transform transforming a select} or if the {@link #store field name is autogenerated based on
         * the store configuration}).
         * <p>See also <tt>{@link #valueField}</tt>.</p>
         * <p><b>Note</b>: if using a ComboBox in an {@link Ext.grid.EditorGridPanel Editor Grid} a
         * {@link Ext.grid.Column#renderer renderer} will be needed to show the displayField when the editor is not
         * active.</p>
         */
        /**
         * @cfg {String} valueField The underlying {@link Ext.data.Field#name data value name} to bind to this
         * ComboBox (defaults to undefined if <tt>{@link #mode} = 'remote'</tt> or <tt>'field2'</tt> if
         * {@link #transform transforming a select} or if the {@link #store field name is autogenerated based on
         * the store configuration}).
         * <p><b>Note</b>: use of a <tt>valueField</tt> requires the user to make a selection in order for a value to be
         * mapped.  See also <tt>{@link #hiddenName}</tt>, <tt>{@link #hiddenValue}</tt>, and <tt>{@link #displayField}</tt>.</p>
         */
        /**
         * @cfg {String} hiddenName If specified, a hidden form field with this name is dynamically generated to store the
         * field's data value (defaults to the underlying DOM element's name). Required for the combo's value to automatically
         * post during a form submission.  See also {@link #valueField}.
         */
        /**
         * @cfg {String} hiddenId If <tt>{@link #hiddenName}</tt> is specified, <tt>hiddenId</tt> can also be provided
         * to give the hidden field a unique id.  The <tt>hiddenId</tt> and combo {@link Ext.Component#id id} should be
         * different, since no two DOM nodes should share the same id.
         */
        /**
         * @cfg {String} hiddenValue Sets the initial value of the hidden field if {@link #hiddenName} is
         * specified to contain the selected {@link #valueField}, from the Store. Defaults to the configured
         * <tt>{@link Ext.form.Field#value value}</tt>.
         */
        /**
         * @cfg {String} listClass The CSS class to add to the predefined <tt>'x-combo-list'</tt> class
         * applied the dropdown list element (defaults to '').
         */
        listClass : '',
        /**
         * @cfg {String} selectedClass CSS class to apply to the selected item in the dropdown list
         * (defaults to <tt>'x-combo-selected'</tt>)
         */
        selectedClass : 'x-combo-selected',
        /**
         * @cfg {String} listEmptyText The empty text to display in the data view if no items are found.
         * (defaults to '')
         */
        listEmptyText: '',
        /**
         * @cfg {String} triggerClass An additional CSS class used to style the trigger button.  The trigger will always
         * get the class <tt>'x-form-trigger'</tt> and <tt>triggerClass</tt> will be <b>appended</b> if specified
         * (defaults to <tt>'x-form-arrow-trigger'</tt> which displays a downward arrow icon).
         */
        triggerClass : 'x-form-arrow-trigger',
        /**
         * @cfg {Boolean/String} shadow <tt>true</tt> or <tt>"sides"</tt> for the default effect, <tt>"frame"</tt> for
         * 4-way shadow, and <tt>"drop"</tt> for bottom-right
         */
        shadow : 'sides',
        /**
         * @cfg {String/Array} listAlign A valid anchor position value. See <tt>{@link Ext.Element#alignTo}</tt> for details
         * on supported anchor positions and offsets. To specify x/y offsets as well, this value
         * may be specified as an Array of <tt>{@link Ext.Element#alignTo}</tt> method arguments.</p>
         * <pre><code>[ 'tl-bl?', [6,0] ]</code></pre>(defaults to <tt>'tl-bl?'</tt>)
         */
        listAlign : 'tl-bl?',
        /**
         * @cfg {Number} maxHeight The maximum height in pixels of the dropdown list before scrollbars are shown
         * (defaults to <tt>300</tt>)
         */
        maxHeight : 300,
        /**
         * @cfg {Number} minHeight The minimum height in pixels of the dropdown list when the list is constrained by its
         * distance to the viewport edges (defaults to <tt>90</tt>)
         */
        minHeight : 90,
        /**
         * @cfg {String} triggerAction The action to execute when the trigger is clicked.
         * <div class="mdetail-params"><ul>
         * <li><b><tt>'query'</tt></b> : <b>Default</b>
         * <p class="sub-desc">{@link #doQuery run the query} using the {@link Ext.form.Field#getRawValue raw value}.</p></li>
         * <li><b><tt>'all'</tt></b> :
         * <p class="sub-desc">{@link #doQuery run the query} specified by the <tt>{@link #allQuery}</tt> config option</p></li>
         * </ul></div>
         * <p>See also <code>{@link #queryParam}</code>.</p>
         */
        triggerAction : 'query',
        /**
         * @cfg {Number} minChars The minimum number of characters the user must type before autocomplete and
         * {@link #typeAhead} activate (defaults to <tt>4</tt> if <tt>{@link #mode} = 'remote'</tt> or <tt>0</tt> if
         * <tt>{@link #mode} = 'local'</tt>, does not apply if
         * <tt>{@link Ext.form.TriggerField#editable editable} = false</tt>).
         */
        minChars : 4,
        /**
         * @cfg {Boolean} autoSelect <tt>true</tt> to select the first result gathered by the data store (defaults
         * to <tt>true</tt>).  A false value would require a manual selection from the dropdown list to set the components value
         * unless the value of ({@link #typeAheadDelay}) were true.
         */
        autoSelect : true,
        /**
         * @cfg {Boolean} typeAhead <tt>true</tt> to populate and autoselect the remainder of the text being
         * typed after a configurable delay ({@link #typeAheadDelay}) if it matches a known value (defaults
         * to <tt>false</tt>)
         */
        typeAhead : false,
        /**
         * @cfg {Number} queryDelay The length of time in milliseconds to delay between the start of typing and
         * sending the query to filter the dropdown list (defaults to <tt>500</tt> if <tt>{@link #mode} = 'remote'</tt>
         * or <tt>10</tt> if <tt>{@link #mode} = 'local'</tt>)
         */
        queryDelay : 500,
        /**
         * @cfg {Number} pageSize If greater than <tt>0</tt>, a {@link Ext.PagingToolbar} is displayed in the
         * footer of the dropdown list and the {@link #doQuery filter queries} will execute with page start and
         * {@link Ext.PagingToolbar#pageSize limit} parameters. Only applies when <tt>{@link #mode} = 'remote'</tt>
         * (defaults to <tt>0</tt>).
         */
        pageSize : 0,
        /**
         * @cfg {Boolean} selectOnFocus <tt>true</tt> to select any existing text in the field immediately on focus.
         * Only applies when <tt>{@link Ext.form.TriggerField#editable editable} = true</tt> (defaults to
         * <tt>false</tt>).
         */
        selectOnFocus : false,
        /**
         * @cfg {String} queryParam Name of the query ({@link Ext.data.Store#baseParam baseParam} name for the store)
         * as it will be passed on the querystring (defaults to <tt>'query'</tt>)
         */
        queryParam : 'query',
        /**
         * @cfg {String} loadingText The text to display in the dropdown list while data is loading.  Only applies
         * when <tt>{@link #mode} = 'remote'</tt> (defaults to <tt>'Loading...'</tt>)
         */
        loadingText : 'Loading...',
        /**
         * @cfg {Boolean} resizable <tt>true</tt> to add a resize handle to the bottom of the dropdown list
         * (creates an {@link Ext.Resizable} with 'se' {@link Ext.Resizable#pinned pinned} handles).
         * Defaults to <tt>false</tt>.
         */
        resizable : false,
        /**
         * @cfg {Number} handleHeight The height in pixels of the dropdown list resize handle if
         * <tt>{@link #resizable} = true</tt> (defaults to <tt>8</tt>)
         */
        handleHeight : 8,
        /**
         * @cfg {String} allQuery The text query to send to the server to return all records for the list
         * with no filtering (defaults to '')
         */
        allQuery: '',
        /**
         * @cfg {String} mode Acceptable values are:
         * <div class="mdetail-params"><ul>
         * <li><b><tt>'remote'</tt></b> : <b>Default</b>
         * <p class="sub-desc">Automatically loads the <tt>{@link #store}</tt> the <b>first</b> time the trigger
         * is clicked. If you do not want the store to be automatically loaded the first time the trigger is
         * clicked, set to <tt>'local'</tt> and manually load the store.  To force a requery of the store
         * <b>every</b> time the trigger is clicked see <tt>{@link #lastQuery}</tt>.</p></li>
         * <li><b><tt>'local'</tt></b> :
         * <p class="sub-desc">ComboBox loads local data</p>
         * <pre><code>
    var combo = new Ext.form.ComboBox({
        renderTo: document.body,
        mode: 'local',
        store: new Ext.data.ArrayStore({
            id: 0,
            fields: [
                'myId',  // numeric value is the key
                'displayText'
            ],
            data: [[1, 'item1'], [2, 'item2']]  // data is local
        }),
        valueField: 'myId',
        displayField: 'displayText',
        triggerAction: 'all'
    });
         * </code></pre></li>
         * </ul></div>
         */
        mode: 'remote',
        /**
         * @cfg {Number} minListWidth The minimum width of the dropdown list in pixels (defaults to <tt>70</tt>, will
         * be ignored if <tt>{@link #listWidth}</tt> has a higher value)
         */
        minListWidth : 70,
        /**
         * @cfg {Boolean} forceSelection <tt>true</tt> to restrict the selected value to one of the values in the list,
         * <tt>false</tt> to allow the user to set arbitrary text into the field (defaults to <tt>false</tt>)
         */
        forceSelection : false,
        /**
         * @cfg {Number} typeAheadDelay The length of time in milliseconds to wait until the typeahead text is displayed
         * if <tt>{@link #typeAhead} = true</tt> (defaults to <tt>250</tt>)
         */
        typeAheadDelay : 250,
        /**
         * @cfg {String} valueNotFoundText When using a name/value combo, if the value passed to setValue is not found in
         * the store, valueNotFoundText will be displayed as the field text if defined (defaults to undefined). If this
         * default text is used, it means there is no value set and no validation will occur on this field.
         */

        /**
         * @cfg {Boolean} lazyInit <tt>true</tt> to not initialize the list for this combo until the field is focused
         * (defaults to <tt>true</tt>)
         */
        lazyInit : true,

        /**
         * @cfg {Boolean} clearFilterOnReset <tt>true</tt> to clear any filters on the store (when in local mode) when reset is called
         * (defaults to <tt>true</tt>)
         */
        clearFilterOnReset : true,

        /**
         * @cfg {Boolean} submitValue False to clear the name attribute on the field so that it is not submitted during a form post.
         * If a hiddenName is specified, setting this to true will cause both the hidden field and the element to be submitted.
         * Defaults to <tt>undefined</tt>.
         */
        submitValue: undefined,

        /**
         * The value of the match string used to filter the store. Delete this property to force a requery.
         * Example use:
         * <pre><code>
    var combo = new Ext.form.ComboBox({
        ...
        mode: 'remote',
        ...
        listeners: {
            // delete the previous query in the beforequery event or set
            // combo.lastQuery = null (this will reload the store the next time it expands)
            beforequery: function(qe){
                delete qe.combo.lastQuery;
            }
        }
    });
         * </code></pre>
         * To make sure the filter in the store is not cleared the first time the ComboBox trigger is used
         * configure the combo with <tt>lastQuery=''</tt>. Example use:
         * <pre><code>
    var combo = new Ext.form.ComboBox({
        ...
        mode: 'local',
        triggerAction: 'all',
        lastQuery: ''
    });
         * </code></pre>
         * @property lastQuery
         * @type String
         */

        // private
        initComponent : function(){
            Ext.form.ComboBox.superclass.initComponent.call(this);
            this.addEvents(
                /**
                 * @event expand
                 * Fires when the dropdown list is expanded
                 * @param {Ext.form.ComboBox} combo This combo box
                 */
                'expand',
                /**
                 * @event collapse
                 * Fires when the dropdown list is collapsed
                 * @param {Ext.form.ComboBox} combo This combo box
                 */
                'collapse',

                /**
                 * @event beforeselect
                 * Fires before a list item is selected. Return false to cancel the selection.
                 * @param {Ext.form.ComboBox} combo This combo box
                 * @param {Ext.data.Record} record The data record returned from the underlying store
                 * @param {Number} index The index of the selected item in the dropdown list
                 */
                'beforeselect',
                /**
                 * @event select
                 * Fires when a list item is selected
                 * @param {Ext.form.ComboBox} combo This combo box
                 * @param {Ext.data.Record} record The data record returned from the underlying store
                 * @param {Number} index The index of the selected item in the dropdown list
                 */
                'select',
                /**
                 * @event beforequery
                 * Fires before all queries are processed. Return false to cancel the query or set the queryEvent's
                 * cancel property to true.
                 * @param {Object} queryEvent An object that has these properties:<ul>
                 * <li><code>combo</code> : Ext.form.ComboBox <div class="sub-desc">This combo box</div></li>
                 * <li><code>query</code> : String <div class="sub-desc">The query</div></li>
                 * <li><code>forceAll</code> : Boolean <div class="sub-desc">True to force "all" query</div></li>
                 * <li><code>cancel</code> : Boolean <div class="sub-desc">Set to true to cancel the query</div></li>
                 * </ul>
                 */
                'beforequery'
            );
            if(this.transform){
                var s = Ext.getDom(this.transform);
                if(!this.hiddenName){
                    this.hiddenName = s.name;
                }
                if(!this.store){
                    this.mode = 'local';
                    var d = [], opts = s.options;
                    for(var i = 0, len = opts.length;i < len; i++){
                        var o = opts[i],
                            value = (o.hasAttribute ? o.hasAttribute('value') : o.getAttributeNode('value').specified) ? o.value : o.text;
                        if(o.selected && Ext.isEmpty(this.value, true)) {
                            this.value = value;
                        }
                        d.push([value, o.text]);
                    }
                    this.store = new Ext.data.ArrayStore({
                        idIndex: 0,
                        fields: ['value', 'text'],
                        data : d,
                        autoDestroy: true
                    });
                    this.valueField = 'value';
                    this.displayField = 'text';
                }
                s.name = Ext.id(); // wipe out the name in case somewhere else they have a reference
                if(!this.lazyRender){
                    this.target = true;
                    this.el = Ext.DomHelper.insertBefore(s, this.autoCreate || this.defaultAutoCreate);
                    this.render(this.el.parentNode, s);
                }
                Ext.removeNode(s);
            }
            //auto-configure store from local array data
            else if(this.store){
                this.store = Ext.StoreMgr.lookup(this.store);
                if(this.store.autoCreated){
                    this.displayField = this.valueField = 'field1';
                    if(!this.store.expandData){
                        this.displayField = 'field2';
                    }
                    this.mode = 'local';
                }
            }

            this.selectedIndex = -1;
            if(this.mode == 'local'){
                if(!Ext.isDefined(this.initialConfig.queryDelay)){
                    this.queryDelay = 10;
                }
                if(!Ext.isDefined(this.initialConfig.minChars)){
                    this.minChars = 0;
                }
            }
        },

        // private
        onRender : function(ct, position){
            if(this.hiddenName && !Ext.isDefined(this.submitValue)){
                this.submitValue = false;
            }
            Ext.form.ComboBox.superclass.onRender.call(this, ct, position);
            if(this.hiddenName){
                this.hiddenField = this.el.insertSibling({tag:'input', type:'hidden', name: this.hiddenName,
                        id: (this.hiddenId || Ext.id())}, 'before', true);

            }
            if(Ext.isGecko){
                this.el.dom.setAttribute('autocomplete', 'off');
            }

            if(!this.lazyInit){
                this.initList();
            }else{
                this.on('focus', this.initList, this, {single: true});
            }
        },

        // private
        initValue : function(){
            Ext.form.ComboBox.superclass.initValue.call(this);
            if(this.hiddenField){
                this.hiddenField.value =
                    Ext.value(Ext.isDefined(this.hiddenValue) ? this.hiddenValue : this.value, '');
            }
        },

        getParentZIndex : function(){
            var zindex;
            if (this.ownerCt){
                this.findParentBy(function(ct){
                    zindex = parseInt(ct.getPositionEl().getStyle('z-index'), 10);
                    return !!zindex;
                });
            }
            return zindex;
        },

        getZIndex : function(listParent){
            listParent = listParent || Ext.getDom(this.getListParent() || Ext.getBody());
            var zindex = parseInt(Ext.fly(listParent).getStyle('z-index'), 10);
            if(!zindex){
                zindex = this.getParentZIndex();
            }
            return (zindex || 12000) + 5;
        },

        // private
        initList : function(){
            if(!this.list){
                var cls = 'x-combo-list',
                    listParent = Ext.getDom(this.getListParent() || Ext.getBody());

                this.list = new Ext.Layer({
                    parentEl: listParent,
                    shadow: this.shadow,
                    cls: [cls, this.listClass].join(' '),
                    constrain:false,
                    zindex: this.getZIndex(listParent)
                });

                var lw = this.listWidth || Math.max(this.wrap.getWidth(), this.minListWidth);
                this.list.setSize(lw, 0);
                this.list.swallowEvent('mousewheel');
                this.assetHeight = 0;
                if(this.syncFont !== false){
                    this.list.setStyle('font-size', this.el.getStyle('font-size'));
                }
                if(this.title){
                    this.header = this.list.createChild({cls:cls+'-hd', html: this.title});
                    this.assetHeight += this.header.getHeight();
                }

                this.innerList = this.list.createChild({cls:cls+'-inner'});
                this.mon(this.innerList, 'mouseover', this.onViewOver, this);
                this.mon(this.innerList, 'mousemove', this.onViewMove, this);
                this.innerList.setWidth(lw - this.list.getFrameWidth('lr'));

                if(this.pageSize){
                    this.footer = this.list.createChild({cls:cls+'-ft'});
                    this.pageTb = new Ext.PagingToolbar({
                        store: this.store,
                        pageSize: this.pageSize,
                        renderTo:this.footer
                    });
                    this.assetHeight += this.footer.getHeight();
                }

                if(!this.tpl){
                    /**
                    * @cfg {String/Ext.XTemplate} tpl <p>The template string, or {@link Ext.XTemplate} instance to
                    * use to display each item in the dropdown list. The dropdown list is displayed in a
                    * DataView. See {@link #view}.</p>
                    * <p>The default template string is:</p><pre><code>
                      '&lt;tpl for=".">&lt;div class="x-combo-list-item">{' + this.displayField + '}&lt;/div>&lt;/tpl>'
                    * </code></pre>
                    * <p>Override the default value to create custom UI layouts for items in the list.
                    * For example:</p><pre><code>
                      '&lt;tpl for=".">&lt;div ext:qtip="{state}. {nick}" class="x-combo-list-item">{state}&lt;/div>&lt;/tpl>'
                    * </code></pre>
                    * <p>The template <b>must</b> contain one or more substitution parameters using field
                    * names from the Combo's</b> {@link #store Store}. In the example above an
                    * <pre>ext:qtip</pre> attribute is added to display other fields from the Store.</p>
                    * <p>To preserve the default visual look of list items, add the CSS class name
                    * <pre>x-combo-list-item</pre> to the template's container element.</p>
                    * <p>Also see {@link #itemSelector} for additional details.</p>
                    */
                    this.tpl = '<tpl for="."><div class="'+cls+'-item">{' + this.displayField + '}</div></tpl>';
                    /**
                     * @cfg {String} itemSelector
                     * <p>A simple CSS selector (e.g. div.some-class or span:first-child) that will be
                     * used to determine what nodes the {@link #view Ext.DataView} which handles the dropdown
                     * display will be working with.</p>
                     * <p><b>Note</b>: this setting is <b>required</b> if a custom XTemplate has been
                     * specified in {@link #tpl} which assigns a class other than <pre>'x-combo-list-item'</pre>
                     * to dropdown list items</b>
                     */
                }

                /**
                * The {@link Ext.DataView DataView} used to display the ComboBox's options.
                * @type Ext.DataView
                */
                this.view = new Ext.DataView({
                    applyTo: this.innerList,
                    tpl: this.tpl,
                    singleSelect: true,
                    selectedClass: this.selectedClass,
                    itemSelector: this.itemSelector || '.' + cls + '-item',
                    emptyText: this.listEmptyText,
                    deferEmptyText: false
                });

                this.mon(this.view, {
                    containerclick : this.onViewClick,
                    click : this.onViewClick,
                    scope :this
                });

                this.bindStore(this.store, true);

                if(this.resizable){
                    this.resizer = new Ext.Resizable(this.list,  {
                       pinned:true, handles:'se'
                    });
                    this.mon(this.resizer, 'resize', function(r, w, h){
                        this.maxHeight = h-this.handleHeight-this.list.getFrameWidth('tb')-this.assetHeight;
                        this.listWidth = w;
                        this.innerList.setWidth(w - this.list.getFrameWidth('lr'));
                        this.restrictHeight();
                    }, this);

                    this[this.pageSize?'footer':'innerList'].setStyle('margin-bottom', this.handleHeight+'px');
                }
            }
        },

        /**
         * <p>Returns the element used to house this ComboBox's pop-up list. Defaults to the document body.</p>
         * A custom implementation may be provided as a configuration option if the floating list needs to be rendered
         * to a different Element. An example might be rendering the list inside a Menu so that clicking
         * the list does not hide the Menu:<pre><code>
    var store = new Ext.data.ArrayStore({
        autoDestroy: true,
        fields: ['initials', 'fullname'],
        data : [
            ['FF', 'Fred Flintstone'],
            ['BR', 'Barney Rubble']
        ]
    });

    var combo = new Ext.form.ComboBox({
        store: store,
        displayField: 'fullname',
        emptyText: 'Select a name...',
        forceSelection: true,
        getListParent: function() {
            return this.el.up('.x-menu');
        },
        iconCls: 'no-icon', //use iconCls if placing within menu to shift to right side of menu
        mode: 'local',
        selectOnFocus: true,
        triggerAction: 'all',
        typeAhead: true,
        width: 135
    });

    var menu = new Ext.menu.Menu({
        id: 'mainMenu',
        items: [
            combo // A Field in a Menu
        ]
    });
    </code></pre>
         */
        getListParent : function() {
            return document.body;
        },

        /**
         * Returns the store associated with this combo.
         * @return {Ext.data.Store} The store
         */
        getStore : function(){
            return this.store;
        },

        // private
        bindStore : function(store, initial){
            if(this.store && !initial){
                if(this.store !== store && this.store.autoDestroy){
                    this.store.destroy();
                }else{
                    this.store.un('beforeload', this.onBeforeLoad, this);
                    this.store.un('load', this.onLoad, this);
                    this.store.un('exception', this.collapse, this);
                }
                if(!store){
                    this.store = null;
                    if(this.view){
                        this.view.bindStore(null);
                    }
                    if(this.pageTb){
                        this.pageTb.bindStore(null);
                    }
                }
            }
            if(store){
                if(!initial) {
                    this.lastQuery = null;
                    if(this.pageTb) {
                        this.pageTb.bindStore(store);
                    }
                }

                this.store = Ext.StoreMgr.lookup(store);
                this.store.on({
                    scope: this,
                    beforeload: this.onBeforeLoad,
                    load: this.onLoad,
                    exception: this.collapse
                });

                if(this.view){
                    this.view.bindStore(store);
                }
            }
        },

        reset : function(){
            if(this.clearFilterOnReset && this.mode == 'local'){
                this.store.clearFilter();
            }
            Ext.form.ComboBox.superclass.reset.call(this);
        },

        // private
        initEvents : function(){
            Ext.form.ComboBox.superclass.initEvents.call(this);

            /**
             * @property keyNav
             * @type Ext.KeyNav
             * <p>A {@link Ext.KeyNav KeyNav} object which handles navigation keys for this ComboBox. This performs actions
             * based on keystrokes typed when the input field is focused.</p>
             * <p><b>After the ComboBox has been rendered</b>, you may override existing navigation key functionality,
             * or add your own based upon key names as specified in the {@link Ext.KeyNav KeyNav} class.</p>
             * <p>The function is executed in the scope (<code>this</code> reference of the ComboBox. Example:</p><pre><code>
    myCombo.keyNav.esc = function(e) {  // Override ESC handling function
        this.collapse();                // Standard behaviour of Ext's ComboBox.
        this.setValue(this.startValue); // We reset to starting value on ESC
    };
    myCombo.keyNav.tab = function() {   // Override TAB handling function
        this.onViewClick(false);        // Select the currently highlighted row
    };
    </code></pre>
             */
            this.keyNav = new Ext.KeyNav(this.el, {
                "up" : function(e){
                    this.inKeyMode = true;
                    this.selectPrev();
                },

                "down" : function(e){
                    if(!this.isExpanded()){
                        this.onTriggerClick();
                    }else{
                        this.inKeyMode = true;
                        this.selectNext();
                    }
                },

                "enter" : function(e){
                    this.onViewClick();
                },

                "esc" : function(e){
                    this.collapse();
                },

                "tab" : function(e){
                    if (this.forceSelection === true) {
                        this.collapse();
                    } else {
                        this.onViewClick(false);
                    }
                    return true;
                },

                scope : this,

                doRelay : function(e, h, hname){
                    if(hname == 'down' || this.scope.isExpanded()){
                        // this MUST be called before ComboBox#fireKey()
                        var relay = Ext.KeyNav.prototype.doRelay.apply(this, arguments);
                        if((((Ext.isIE9 && Ext.isStrict) || Ext.isIE10p) || !Ext.isIE) && Ext.EventManager.useKeydown){
                            // call Combo#fireKey() for browsers which use keydown event (except IE)
                            this.scope.fireKey(e);
                        }
                        return relay;
                    }
                    return true;
                },

                forceKeyDown : true,
                defaultEventAction: 'stopEvent'
            });
            this.queryDelay = Math.max(this.queryDelay || 10,
                    this.mode == 'local' ? 10 : 250);
            this.dqTask = new Ext.util.DelayedTask(this.initQuery, this);
            if(this.typeAhead){
                this.taTask = new Ext.util.DelayedTask(this.onTypeAhead, this);
            }
            if(!this.enableKeyEvents){
                this.mon(this.el, 'keyup', this.onKeyUp, this);
            }
        },

        // private
        onDestroy : function(){
            if (this.dqTask){
                this.dqTask.cancel();
                this.dqTask = null;
            }
            this.bindStore(null);
            Ext.destroy(
                this.resizer,
                this.view,
                this.pageTb,
                this.list
            );
            Ext.destroyMembers(this, 'hiddenField');
            Ext.form.ComboBox.superclass.onDestroy.call(this);
        },

        // private
        fireKey : function(e){
            if (!this.isExpanded()) {
                Ext.form.ComboBox.superclass.fireKey.call(this, e);
            }
        },

        // private
        onResize : function(w, h){
            Ext.form.ComboBox.superclass.onResize.apply(this, arguments);
            if(!isNaN(w) && this.isVisible() && this.list){
                this.doResize(w);
            }else{
                this.bufferSize = w;
            }
        },

        doResize: function(w){
            if(!Ext.isDefined(this.listWidth)){
                var lw = Math.max(w, this.minListWidth);
                this.list.setWidth(lw);
                this.innerList.setWidth(lw - this.list.getFrameWidth('lr'));
            }
        },

        // private
        onEnable : function(){
            Ext.form.ComboBox.superclass.onEnable.apply(this, arguments);
            if(this.hiddenField){
                this.hiddenField.disabled = false;
            }
        },

        // private
        onDisable : function(){
            Ext.form.ComboBox.superclass.onDisable.apply(this, arguments);
            if(this.hiddenField){
                this.hiddenField.disabled = true;
            }
        },

        // private
        onBeforeLoad : function(){
            if(!this.hasFocus){
                return;
            }
            this.innerList.update(this.loadingText ?
                   '<div class="loading-indicator">'+this.loadingText+'</div>' : '');
            this.restrictHeight();
            this.selectedIndex = -1;
        },

        // private
        onLoad : function(){
            if(!this.hasFocus){
                return;
            }
            if(this.store.getCount() > 0 || this.listEmptyText){
                this.expand();
                this.restrictHeight();
                if(this.lastQuery == this.allQuery){
                    if(this.editable){
                        this.el.dom.select();
                    }

                    if(this.autoSelect !== false && !this.selectByValue(this.value, true)){
                        this.select(0, true);
                    }
                }else{
                    if(this.autoSelect !== false){
                        this.selectNext();
                    }
                    if(this.typeAhead && this.lastKey != Ext.EventObject.BACKSPACE && this.lastKey != Ext.EventObject.DELETE){
                        this.taTask.delay(this.typeAheadDelay);
                    }
                }
            }else{
                this.collapse();
            }

        },

        // private
        onTypeAhead : function(){
            if(this.store.getCount() > 0){
                var r = this.store.getAt(0);
                var newValue = r.data[this.displayField];
                var len = newValue.length;
                var selStart = this.getRawValue().length;
                if(selStart != len){
                    this.setRawValue(newValue);
                    this.selectText(selStart, newValue.length);
                }
            }
        },

        // private
        assertValue : function(){
            var val = this.getRawValue(),
                rec;

            if(this.valueField && Ext.isDefined(this.value)){
                rec = this.findRecord(this.valueField, this.value);
            }
            if(!rec || rec.get(this.displayField) != val){
                rec = this.findRecord(this.displayField, val);
            }
            if(!rec && this.forceSelection){
                if(val.length > 0 && val != this.emptyText){
                    this.el.dom.value = Ext.value(this.lastSelectionText, '');
                    this.applyEmptyText();
                }else{
                    this.clearValue();
                }
            }else{
                if(rec && this.valueField){
                    // onSelect may have already set the value and by doing so
                    // set the display field properly.  Let's not wipe out the
                    // valueField here by just sending the displayField.
                    if (this.value == val){
                        return;
                    }
                    val = rec.get(this.valueField || this.displayField);
                }
                this.setValue(val);
            }
        },

        // private
        onSelect : function(record, index){
            if(this.fireEvent('beforeselect', this, record, index) !== false){
                this.setValue(record.data[this.valueField || this.displayField]);
                this.collapse();
                this.fireEvent('select', this, record, index);
            }
        },

        // inherit docs
        getName: function(){
            var hf = this.hiddenField;
            return hf && hf.name ? hf.name : this.hiddenName || Ext.form.ComboBox.superclass.getName.call(this);
        },

        /**
         * Returns the currently selected field value or empty string if no value is set.
         * @return {String} value The selected value
         */
        getValue : function(){
            if(this.valueField){
                return Ext.isDefined(this.value) ? this.value : '';
            }else{
                return Ext.form.ComboBox.superclass.getValue.call(this);
            }
        },

        /**
         * Clears any text/value currently set in the field
         */
        clearValue : function(){
            if(this.hiddenField){
                this.hiddenField.value = '';
            }
            this.setRawValue('');
            this.lastSelectionText = '';
            this.applyEmptyText();
            this.value = '';
        },

        /**
         * Sets the specified value into the field.  If the value finds a match, the corresponding record text
         * will be displayed in the field.  If the value does not match the data value of an existing item,
         * and the valueNotFoundText config option is defined, it will be displayed as the default field text.
         * Otherwise the field will be blank (although the value will still be set).
         * @param {String} value The value to match
         * @return {Ext.form.Field} this
         */
        setValue : function(v){
            var text = v;
            if(this.valueField){
                var r = this.findRecord(this.valueField, v);
                if(r){
                    text = r.data[this.displayField];
                }else if(Ext.isDefined(this.valueNotFoundText)){
                    text = this.valueNotFoundText;
                }
            }
            this.lastSelectionText = text;
            if(this.hiddenField){
                this.hiddenField.value = Ext.value(v, '');
            }
            Ext.form.ComboBox.superclass.setValue.call(this, text);
            this.value = v;
            return this;
        },

        // private
        findRecord : function(prop, value){
            var record;
            if(this.store.getCount() > 0){
                this.store.each(function(r){
                    if(r.data[prop] == value){
                        record = r;
                        return false;
                    }
                });
            }
            return record;
        },

        // private
        onViewMove : function(e, t){
            this.inKeyMode = false;
        },

        // private
        onViewOver : function(e, t){
            if(this.inKeyMode){ // prevent key nav and mouse over conflicts
                return;
            }
            var item = this.view.findItemFromChild(t);
            if(item){
                var index = this.view.indexOf(item);
                this.select(index, false);
            }
        },

        // private
        onViewClick : function(doFocus){
            var index = this.view.getSelectedIndexes()[0],
                s = this.store,
                r = s.getAt(index);
            if(r){
                this.onSelect(r, index);
            }else {
                this.collapse();
            }
            if(doFocus !== false){
                this.el.focus();
            }
        },

        // private
        restrictHeight : function(){
            this.innerList.dom.style.height = '';
            var inner = this.innerList.dom,
                pad = this.list.getFrameWidth('tb') + (this.resizable ? this.handleHeight : 0) + this.assetHeight,
                h = Math.max(inner.clientHeight, inner.offsetHeight, inner.scrollHeight),
                ha = this.getPosition()[1]-Ext.getBody().getScroll().top,
                hb = Ext.lib.Dom.getViewHeight()-ha-this.getSize().height,
                space = Math.max(ha, hb, this.minHeight || 0)-this.list.shadowOffset-pad-5;

            h = Math.min(h, space, this.maxHeight);

            this.innerList.setHeight(h);
            this.list.beginUpdate();
            this.list.setHeight(h+pad);
            this.list.alignTo.apply(this.list, [this.el].concat(this.listAlign));
            this.list.endUpdate();
        },

        /**
         * Returns true if the dropdown list is expanded, else false.
         */
        isExpanded : function(){
            return this.list && this.list.isVisible();
        },

        /**
         * Select an item in the dropdown list by its data value. This function does NOT cause the select event to fire.
         * The store must be loaded and the list expanded for this function to work, otherwise use setValue.
         * @param {String} value The data value of the item to select
         * @param {Boolean} scrollIntoView False to prevent the dropdown list from autoscrolling to display the
         * selected item if it is not currently in view (defaults to true)
         * @return {Boolean} True if the value matched an item in the list, else false
         */
        selectByValue : function(v, scrollIntoView){
            if(!Ext.isEmpty(v, true)){
                var r = this.findRecord(this.valueField || this.displayField, v);
                if(r){
                    this.select(this.store.indexOf(r), scrollIntoView);
                    return true;
                }
            }
            return false;
        },

        /**
         * Select an item in the dropdown list by its numeric index in the list. This function does NOT cause the select event to fire.
         * The store must be loaded and the list expanded for this function to work, otherwise use setValue.
         * @param {Number} index The zero-based index of the list item to select
         * @param {Boolean} scrollIntoView False to prevent the dropdown list from autoscrolling to display the
         * selected item if it is not currently in view (defaults to true)
         */
        select : function(index, scrollIntoView){
            this.selectedIndex = index;
            this.view.select(index);
            if(scrollIntoView !== false){
                var el = this.view.getNode(index);
                if(el){
                    this.innerList.scrollChildIntoView(el, false);
                }
            }

        },

        // private
        selectNext : function(){
            var ct = this.store.getCount();
            if(ct > 0){
                if(this.selectedIndex == -1){
                    this.select(0);
                }else if(this.selectedIndex < ct-1){
                    this.select(this.selectedIndex+1);
                }
            }
        },

        // private
        selectPrev : function(){
            var ct = this.store.getCount();
            if(ct > 0){
                if(this.selectedIndex == -1){
                    this.select(0);
                }else if(this.selectedIndex !== 0){
                    this.select(this.selectedIndex-1);
                }
            }
        },

        // private
        onKeyUp : function(e){
            var k = e.getKey();
            if(this.editable !== false && this.readOnly !== true && (k == e.BACKSPACE || !e.isSpecialKey())){

                this.lastKey = k;
                this.dqTask.delay(this.queryDelay);
            }
            Ext.form.ComboBox.superclass.onKeyUp.call(this, e);
        },

        // private
        validateBlur : function(){
            return !this.list || !this.list.isVisible();
        },

        // private
        initQuery : function(){
            this.doQuery(this.getRawValue());
        },

        // private
        beforeBlur : function(){
            this.assertValue();
        },

        // private
        postBlur  : function(){
            Ext.form.ComboBox.superclass.postBlur.call(this);
            this.collapse();
            this.inKeyMode = false;
        },

        /**
         * Execute a query to filter the dropdown list.  Fires the {@link #beforequery} event prior to performing the
         * query allowing the query action to be canceled if needed.
         * @param {String} query The SQL query to execute
         * @param {Boolean} forceAll <tt>true</tt> to force the query to execute even if there are currently fewer
         * characters in the field than the minimum specified by the <tt>{@link #minChars}</tt> config option.  It
         * also clears any filter previously saved in the current store (defaults to <tt>false</tt>)
         */
        doQuery : function(q, forceAll){
            q = Ext.isEmpty(q) ? '' : q;
            var qe = {
                query: q,
                forceAll: forceAll,
                combo: this,
                cancel:false
            };
            if(this.fireEvent('beforequery', qe)===false || qe.cancel){
                return false;
            }
            q = qe.query;
            forceAll = qe.forceAll;
            if(forceAll === true || (q.length >= this.minChars)){
                if(this.lastQuery !== q){
                    this.lastQuery = q;
                    if(this.mode == 'local'){
                        this.selectedIndex = -1;
                        if(forceAll){
                            this.store.clearFilter();
                        }else{
                            this.store.filter(this.displayField, q);
                        }
                        this.onLoad();
                    }else{
                        this.store.baseParams[this.queryParam] = q;
                        this.store.load({
                            params: this.getParams(q)
                        });
                        this.expand();
                    }
                }else{
                    this.selectedIndex = -1;
                    this.onLoad();
                }
            }
        },

        // private
        getParams : function(q){
            var params = {},
                paramNames = this.store.paramNames;
            if(this.pageSize){
                params[paramNames.start] = 0;
                params[paramNames.limit] = this.pageSize;
            }
            return params;
        },

        /**
         * Hides the dropdown list if it is currently expanded. Fires the {@link #collapse} event on completion.
         */
        collapse : function(){
            if(!this.isExpanded()){
                return;
            }
            this.list.hide();
            Ext.getDoc().un('mousewheel', this.collapseIf, this);
            Ext.getDoc().un('mousedown', this.collapseIf, this);
            this.fireEvent('collapse', this);
        },

        // private
        collapseIf : function(e){
            if(!this.isDestroyed && !e.within(this.wrap) && !e.within(this.list)){
                this.collapse();
            }
        },

        /**
         * Expands the dropdown list if it is currently hidden. Fires the {@link #expand} event on completion.
         */
        expand : function(){
            if(this.isExpanded() || !this.hasFocus){
                return;
            }

            if(this.title || this.pageSize){
                this.assetHeight = 0;
                if(this.title){
                    this.assetHeight += this.header.getHeight();
                }
                if(this.pageSize){
                    this.assetHeight += this.footer.getHeight();
                }
            }

            if(this.bufferSize){
                this.doResize(this.bufferSize);
                delete this.bufferSize;
            }
            this.list.alignTo.apply(this.list, [this.el].concat(this.listAlign));

            // zindex can change, re-check it and set it if necessary
            this.list.setZIndex(this.getZIndex());
            this.list.show();
            if(Ext.isGecko2){
                this.innerList.setOverflow('auto'); // necessary for FF 2.0/Mac
            }
            this.mon(Ext.getDoc(), {
                scope: this,
                mousewheel: this.collapseIf,
                mousedown: this.collapseIf
            });
            this.fireEvent('expand', this);
        },

        /**
         * @method onTriggerClick
         * @hide
         */
        // private
        // Implements the default empty TriggerField.onTriggerClick function
        onTriggerClick : function(){
            if(this.readOnly || this.disabled){
                return;
            }
            if(this.isExpanded()){
                this.collapse();
                this.el.focus();
            }else {
                this.onFocus({});
                if(this.triggerAction == 'all') {
                    this.doQuery(this.allQuery, true);
                } else {
                    this.doQuery(this.getRawValue());
                }
                this.el.focus();
            }
        }

        /**
         * @hide
         * @method autoSize
         */
        /**
         * @cfg {Boolean} grow @hide
         */
        /**
         * @cfg {Number} growMin @hide
         */
        /**
         * @cfg {Number} growMax @hide
         */

    });
    Ext.reg('combo', Ext.form.ComboBox);