The source code

    /**
     * @class Ext.ColorPalette
     * @extends Ext.Component
     * Simple color palette class for choosing colors.  The palette can be rendered to any container.<br />
     * Here's an example of typical usage:
     * <pre><code>
    var cp = new Ext.ColorPalette({value:'993300'});  // initial selected color
    cp.render('my-div');

    cp.on('select', function(palette, selColor){
        // do something with selColor
    });
    </code></pre>
     * @constructor
     * Create a new ColorPalette
     * @param {Object} config The config object
     * @xtype colorpalette
     */
    Ext.ColorPalette = Ext.extend(Ext.Component, {
    	/**
    	 * @cfg {String} tpl An existing XTemplate instance to be used in place of the default template for rendering the component.
    	 */
        /**
         * @cfg {String} itemCls
         * The CSS class to apply to the containing element (defaults to 'x-color-palette')
         */
        itemCls : 'x-color-palette',
        /**
         * @cfg {String} value
         * The initial color to highlight (should be a valid 6-digit color hex code without the # symbol).  Note that
         * the hex codes are case-sensitive.
         */
        value : null,
        /**
         * @cfg {String} clickEvent
         * The DOM event that will cause a color to be selected. This can be any valid event name (dblclick, contextmenu).
         * Defaults to <tt>'click'</tt>.
         */
        clickEvent :'click',
        // private
        ctype : 'Ext.ColorPalette',

        /**
         * @cfg {Boolean} allowReselect If set to true then reselecting a color that is already selected fires the {@link #select} event
         */
        allowReselect : false,

        /**
         * <p>An array of 6-digit color hex code strings (without the # symbol).  This array can contain any number
         * of colors, and each hex code should be unique.  The width of the palette is controlled via CSS by adjusting
         * the width property of the 'x-color-palette' class (or assigning a custom class), so you can balance the number
         * of colors with the width setting until the box is symmetrical.</p>
         * <p>You can override individual colors if needed:</p>
         * <pre><code>
    var cp = new Ext.ColorPalette();
    cp.colors[0] = 'FF0000';  // change the first box to red
    </code></pre>

    Or you can provide a custom array of your own for complete control:
    <pre><code>
    var cp = new Ext.ColorPalette();
    cp.colors = ['000000', '993300', '333300'];
    </code></pre>
         * @type Array
         */
        colors : [
            '000000', '993300', '333300', '003300', '003366', '000080', '333399', '333333',
            '800000', 'FF6600', '808000', '008000', '008080', '0000FF', '666699', '808080',
            'FF0000', 'FF9900', '99CC00', '339966', '33CCCC', '3366FF', '800080', '969696',
            'FF00FF', 'FFCC00', 'FFFF00', '00FF00', '00FFFF', '00CCFF', '993366', 'C0C0C0',
            'FF99CC', 'FFCC99', 'FFFF99', 'CCFFCC', 'CCFFFF', '99CCFF', 'CC99FF', 'FFFFFF'
        ],

        /**
         * @cfg {Function} handler
         * Optional. A function that will handle the select event of this palette.
         * The handler is passed the following parameters:<div class="mdetail-params"><ul>
         * <li><code>palette</code> : ColorPalette<div class="sub-desc">The {@link #palette Ext.ColorPalette}.</div></li>
         * <li><code>color</code> : String<div class="sub-desc">The 6-digit color hex code (without the # symbol).</div></li>
         * </ul></div>
         */
        /**
         * @cfg {Object} scope
         * The scope (<tt><b>this</b></tt> reference) in which the <code>{@link #handler}</code>
         * function will be called.  Defaults to this ColorPalette instance.
         */

        // private
        initComponent : function(){
            Ext.ColorPalette.superclass.initComponent.call(this);
            this.addEvents(
                /**
                 * @event select
                 * Fires when a color is selected
                 * @param {ColorPalette} this
                 * @param {String} color The 6-digit color hex code (without the # symbol)
                 */
                'select'
            );

            if(this.handler){
                this.on('select', this.handler, this.scope, true);
            }
        },

        // private
        onRender : function(container, position){
            this.autoEl = {
                tag: 'div',
                cls: this.itemCls
            };
            Ext.ColorPalette.superclass.onRender.call(this, container, position);
            var t = this.tpl || new Ext.XTemplate(
                '<tpl for="."><a href="#" class="color-{.}" hidefocus="on"><em><span style="background:#{.}" class="x-unselectable" unselectable="on">&#160;</span></em></a></tpl>'
            );
            t.overwrite(this.el, this.colors);
            this.mon(this.el, this.clickEvent, this.handleClick, this, {delegate: 'a'});
            if(this.clickEvent != 'click'){
            	this.mon(this.el, 'click', Ext.emptyFn, this, {delegate: 'a', preventDefault: true});
            }
        },

        // private
        afterRender : function(){
            Ext.ColorPalette.superclass.afterRender.call(this);
            if(this.value){
                var s = this.value;
                this.value = null;
                this.select(s, true);
            }
        },

        // private
        handleClick : function(e, t){
            e.preventDefault();
            if(!this.disabled){
                var c = t.className.match(/(?:^|\s)color-(.{6})(?:\s|$)/)[1];
                this.select(c.toUpperCase());
            }
        },

        /**
         * Selects the specified color in the palette (fires the {@link #select} event)
         * @param {String} color A valid 6-digit color hex code (# will be stripped if included)
         * @param {Boolean} suppressEvent (optional) True to stop the select event from firing. Defaults to <tt>false</tt>.
         */
        select : function(color, suppressEvent){
            color = color.replace('#', '');
            if(color != this.value || this.allowReselect){
                var el = this.el;
                if(this.value){
                    el.child('a.color-'+this.value).removeClass('x-color-palette-sel');
                }
                el.child('a.color-'+color).addClass('x-color-palette-sel');
                this.value = color;
                if(suppressEvent !== true){
                    this.fireEvent('select', this, color);
                }
            }
        }

        /**
         * @cfg {String} autoEl @hide
         */
    });
    Ext.reg('colorpalette', Ext.ColorPalette);