The source code

    /*!
     * Ext JS Library 3.3.1
     * Copyright(c) 2006-2010 Sencha Inc.
     * licensing@sencha.com
     * http://www.sencha.com/license
     */
    /**
     * @class Ext.ux.TabCloseMenu
     * @extends Object
     * Plugin (ptype = 'tabclosemenu') for adding a close context menu to tabs. Note that the menu respects
     * the closable configuration on the tab. As such, commands like remove others and remove all will not
     * remove items that are not closable.
     *
     * @constructor
     * @param {Object} config The configuration options
     * @ptype tabclosemenu
     */
    Ext.ux.TabCloseMenu = Ext.extend(Object, {
        /**
         * @cfg {String} closeTabText
         * The text for closing the current tab. Defaults to 'Close Tab'.
         */
        closeTabText: 'Close Tab',

        /**
         * @cfg {String} closeOtherTabsText
         * The text for closing all tabs except the current one. Defaults to 'Close Other Tabs'.
         */
        closeOtherTabsText: 'Close Other Tabs',

        /**
         * @cfg {Boolean} showCloseAll
         * Indicates whether to show the 'Close All' option. Defaults to true.
         */
        showCloseAll: true,

        /**
         * @cfg {String} closeAllTabsText
         * The text for closing all tabs. Defaults to 'Close All Tabs'.
         */
        closeAllTabsText: 'Close All Tabs',

        constructor : function(config){
            Ext.apply(this, config || {});
        },

        //public
        init : function(tabs){
            this.tabs = tabs;
            tabs.on({
                scope: this,
                contextmenu: this.onContextMenu,
                destroy: this.destroy
            });
        },

        destroy : function(){
            Ext.destroy(this.menu);
            delete this.menu;
            delete this.tabs;
            delete this.active;
        },

        // private
        onContextMenu : function(tabs, item, e){
            this.active = item;
            var m = this.createMenu(),
                disableAll = true,
                disableOthers = true,
                closeAll = m.getComponent('closeall');

            m.getComponent('close').setDisabled(!item.closable);
            tabs.items.each(function(){
                if(this.closable){
                    disableAll = false;
                    if(this != item){
                        disableOthers = false;
                        return false;
                    }
                }
            });
            m.getComponent('closeothers').setDisabled(disableOthers);
            if(closeAll){
                closeAll.setDisabled(disableAll);
            }

            e.stopEvent();
            m.showAt(e.getPoint());
        },

        createMenu : function(){
            if(!this.menu){
                var items = [{
                    itemId: 'close',
                    text: this.closeTabText,
                    scope: this,
                    handler: this.onClose
                }];
                if(this.showCloseAll){
                    items.push('-');
                }
                items.push({
                    itemId: 'closeothers',
                    text: this.closeOtherTabsText,
                    scope: this,
                    handler: this.onCloseOthers
                });
                if(this.showCloseAll){
                    items.push({
                        itemId: 'closeall',
                        text: this.closeAllTabsText,
                        scope: this,
                        handler: this.onCloseAll
                    });
                }
                this.menu = new Ext.menu.Menu({
                    items: items
                });
            }
            return this.menu;
        },

        onClose : function(){
            this.tabs.remove(this.active);
        },

        onCloseOthers : function(){
            this.doClose(true);
        },

        onCloseAll : function(){
            this.doClose(false);
        },

        doClose : function(excludeActive){
            var items = [];
            this.tabs.items.each(function(item){
                if(item.closable){
                    if(!excludeActive || item != this.active){
                        items.push(item);
                    }
                }
            }, this);
            Ext.each(items, function(item){
                this.tabs.remove(item);
            }, this);
        }
    });

    Ext.preg('tabclosemenu', Ext.ux.TabCloseMenu);