    /**
     * @private
     */
    Ext.define('Ext.layout.container.boxOverflow.Menu', {

        /* Begin Definitions */

        extend: 'Ext.layout.container.boxOverflow.None',
        requires: ['Ext.toolbar.Separator', 'Ext.button.Button'],
        alternateClassName: 'Ext.layout.boxOverflow.Menu',

        /* End Definitions */

        /**
         * @cfg {String} triggerButtonCls
         * CSS class added to the Button which shows the overflow menu.
         */

        /**
         * @property {String} noItemsMenuText
         * HTML fragment to render into the toolbar overflow menu if there are no items to display
         */
        noItemsMenuText : '<div class="' + Ext.baseCSSPrefix + 'toolbar-no-items">(None)</div>',

        constructor: function(layout) {
            var me = this;

            me.callParent(arguments);

            me.triggerButtonCls = me.triggerButtonCls || Ext.baseCSSPrefix + 'box-menu-after';
            /**
             * @property {Array} menuItems
             * Array of all items that are currently hidden and should go into the dropdown menu
             */
            me.menuItems = [];
        },

        beginLayout: function (ownerContext) {
            this.callParent(arguments);

            // Before layout, we need to re-show all items which we may have hidden due to a
            // previous overflow...
            this.clearOverflow(ownerContext);
        },

        beginLayoutCycle: function (ownerContext, firstCycle) {
            this.callParent(arguments);

            if (!firstCycle) {
                // if we are being re-run, we need to clear any overflow from the last run and
                // recache the childItems collection
                this.clearOverflow(ownerContext);

                this.layout.cacheChildItems(ownerContext);
            }
        },

        onRemove: function(comp){
            Ext.Array.remove(this.menuItems, comp);
        },

        // We don't define a prefix in menu overflow.
        getSuffixConfig: function() {
            var me = this,
                layout = me.layout,
                owner = layout.owner,
                oid = owner.id;

            /**
             * @private
             * @property {Ext.menu.Menu} menu
             * The expand menu - holds items for every item that cannot be shown
             * because the container is currently not large enough.
             */
            me.menu = new Ext.menu.Menu({
                listeners: {
                    scope: me,
                    beforeshow: me.beforeMenuShow
                }
            });

            /**
             * @private
             * @property {Ext.button.Button} menuTrigger
             * The expand button which triggers the overflow menu to be shown
             */
            me.menuTrigger = new Ext.button.Button({
                id: oid + '-menu-trigger',
                cls: Ext.layout.container.Box.prototype.innerCls + ' ' + me.triggerButtonCls + ' ' + Ext.baseCSSPrefix + 'toolbar-item',
                plain: owner.usePlainButtons,
                ownerCt: owner, // To enable the Menu to ascertain a valid zIndexManager owner in the same tree
                ownerLayout: layout,
                iconCls: Ext.baseCSSPrefix + me.getOwnerType(owner) + '-more-icon',
                ui: owner instanceof Ext.toolbar.Toolbar ? 'default-toolbar' : 'default',
                menu: me.menu,
                // Menu will be empty when we're showing it because we populate items after
                showEmptyMenu: true,
                getSplitCls: function() { return '';}
            });

            return me.menuTrigger.getRenderTree();
        },

        getOverflowCls: function() {
            return Ext.baseCSSPrefix + this.layout.direction + '-box-overflow-body';
        },

        handleOverflow: function(ownerContext) {
            var me = this,
                layout = me.layout,
                names = layout.names,
                plan = ownerContext.state.boxPlan,
                posArgs = [null, null];

            me.showTrigger(ownerContext);

            // Center the menuTrigger button only if we are not vertical.
            // TODO: Should we emulate align: 'middle' like this, or should we 'stretchmax' the menuTrigger?
            if (me.layout.direction !== 'vertical') {
                posArgs[names.heightIndex] = (plan.maxSize - me.menuTrigger[names.getHeight]()) / 2;
                me.menuTrigger.setPosition.apply(me.menuTrigger, posArgs);
            }

            return {
                reservedSpace: me.triggerTotalWidth
            };
        },

        /**
         * Finishes the render operation of the trigger Button.
         * @private
         */
        captureChildElements: function() {
            var me = this,
                menuTrigger = me.menuTrigger,
                names = me.layout.names;

            // The rendering flag is set when getRenderTree is called which we do when returning markup string for the owning layout's "suffix"
            if (menuTrigger.rendering) {
                menuTrigger.finishRender();
                me.triggerTotalWidth = menuTrigger[names.getWidth]() + menuTrigger.el.getMargin(names.parallelMargins);
            }
        },

        _asLayoutRoot: { isRoot: true },

        /**
         * @private
         * Called by the layout, when it determines that there is no overflow.
         * Also called as an interceptor to the layout's onLayout method to reshow
         * previously hidden overflowing items.
         */
        clearOverflow: function(ownerContext) {
            var me = this,
                items = me.menuItems,
                item,
                i = 0,
                length = items.length,
                owner = me.layout.owner,
                asLayoutRoot = me._asLayoutRoot;

            owner.suspendLayouts();
            me.captureChildElements();
            me.hideTrigger();
            owner.resumeLayouts();

            for (; i < length; i++) {
                item = items[i];

                // What we are doing here is preventing the layout bubble from invalidating our
                // owner component. We need just the button to be added to the layout run.
                item.suspendLayouts();
                item.show();
                item.resumeLayouts(asLayoutRoot);
            }

            items.length = 0;
        },

        /**
         * @private
         * Shows the overflow trigger when enableOverflow is set to true and the items
         * in the layout are too wide to fit in the space available
         */
        showTrigger: function(ownerContext) {
            var me = this,
                layout = me.layout,
                owner = layout.owner,
                names = layout.names,
                startProp = names.x,
                sizeProp = names.width,
                plan = ownerContext.state.boxPlan,
                available = plan.targetSize[sizeProp],
                childItems = ownerContext.childItems,
                len = childItems.length,
                menuTrigger = me.menuTrigger,
                childContext,
                comp, i, props;

            // We don't want the menuTrigger.show to cause owner's layout to be invalidated, so
            // we force just the button to be invalidated and added to the current run.
            menuTrigger.suspendLayouts();
            menuTrigger.show();
            menuTrigger.resumeLayouts(me._asLayoutRoot);

            available -= me.triggerTotalWidth;

            owner.suspendLayouts();

            // Hide all items which are off the end, and store them to allow them to be restored
            // before each layout operation.
            me.menuItems.length = 0;
            for (i = 0; i < len; i++) {
                childContext = childItems[i];
                props = childContext.props;
                if (props[startProp] + props[sizeProp] > available) {
                    comp = childContext.target;
                    me.menuItems.push(comp);
                    comp.hide();
                }
            }

            owner.resumeLayouts();
        },

        /**
         * @private
         */
        hideTrigger: function() {
            var menuTrigger = this.menuTrigger;
            if (menuTrigger) {
                menuTrigger.hide();
            }
        },

        /**
         * @private
         * Called before the overflow menu is shown. This constructs the menu's items, caching them for as long as it can.
         */
        beforeMenuShow: function(menu) {
            var me = this,
                items = me.menuItems,
                i = 0,
                len   = items.length,
                item,
                prev,
                needsSep = function(group, prev){
                    return group.isXType('buttongroup') && !(prev instanceof Ext.toolbar.Separator);
                };

            menu.suspendLayouts();
            me.clearMenu();
            menu.removeAll();

            for (; i < len; i++) {
                item = items[i];

                // Do not show a separator as a first item
                if (!i && (item instanceof Ext.toolbar.Separator)) {
                    continue;
                }
                if (prev && (needsSep(item, prev) || needsSep(prev, item))) {
                    menu.add('-');
                }

                me.addComponentToMenu(menu, item);
                prev = item;
            }

            // put something so the menu isn't empty if no compatible items found
            if (menu.items.length < 1) {
                menu.add(me.noItemsMenuText);
            }
            menu.resumeLayouts();
        },

        /**
         * @private
         * Returns a menu config for a given component. This config is used to create a menu item
         * to be added to the expander menu
         * @param {Ext.Component} component The component to create the config for
         * @param {Boolean} hideOnClick Passed through to the menu item
         */
        createMenuConfig : function(component, hideOnClick) {
            var me = this,
                config = Ext.apply({}, component.initialConfig),
                group  = component.toggleGroup;

            Ext.copyTo(config, component, [
                'iconCls', 'icon', 'itemId', 'disabled', 'handler', 'scope', 'menu', 'tabIndex'
            ]);

            Ext.apply(config, {
                text       : component.overflowText || component.text,
                hideOnClick: hideOnClick,
                destroyMenu: false,
                listeners  : {}
            });

            // Clone must have same value, and must sync original's value on change
            if (component.isFormField) {
                config.value = component.getValue();

                // Sync the original component's value when the clone changes value.
                // This intentionally overwrites any developer-configured change listener on the clone.
                // That's because we monitor the clone's change event, and sync the
                // original field by calling setValue, so the original field's change
                // event will still fire.
                config.listeners.change = function(c, newVal, oldVal) {
                    component.setValue(newVal);
                }
            }

            // ToggleButtons become CheckItems
            else if (group || component.enableToggle) {
                Ext.apply(config, {
                    hideOnClick: false,
                    group  : group,
                    checked: component.pressed,
                    handler: function(item, e) {
                        component.onClick(e);
                    }
                });
            }

            // Buttons may have their text or icon changed - this must be propagated to the clone in the overflow menu
            if (component.isButton && !component.changeListenersAdded) {
                component.on({
                    textchange: me.onButtonAttrChange,
                    iconchange: me.onButtonAttrChange,
                    toggle:     me.onButtonToggle
                });
                component.changeListenersAdded = true;
            }

            // Typically margins are used to separate items in a toolbar
            // but don't really make a lot of sense in a menu, so we strip
            // them out here.
            delete config.margin;
            delete config.ownerCt;
            delete config.xtype;
            delete config.id;
            delete config.itemId;
            return config;
        },

        onButtonAttrChange: function(btn) {
            var clone = btn.overflowClone;
            clone.suspendLayouts();
            clone.setText(btn.text);
            clone.setIcon(btn.icon);
            clone.setIconCls(btn.iconCls);
            clone.resumeLayouts(true);
        },

        onButtonToggle: function(btn, state) {
            // Keep the clone in sync with the original if necessary
            if (btn.overflowClone.checked !== state) {
                btn.overflowClone.setChecked(state);
            }
        },

        /**
         * @private
         * Adds the given Toolbar item to the given menu. Buttons inside a buttongroup are added individually.
         * @param {Ext.menu.Menu} menu The menu to add to
         * @param {Ext.Component} component The component to add
         * TODO: Implement overrides in Ext.layout.container.boxOverflow which create overrides
         * for SplitButton, Button, ButtonGroup, and TextField. And a generic one for Component
         * which create clones suitable for use in an overflow menu.
         */
        addComponentToMenu : function(menu, component) {
            var me = this,
            i, items, iLen;

            if (component instanceof Ext.toolbar.Separator) {
                menu.add('-');
            } else if (component.isComponent) {
                if (component.isXType('splitbutton')) {
                    component.overflowClone = menu.add(me.createMenuConfig(component, true));

                } else if (component.isXType('button')) {
                    component.overflowClone = menu.add(me.createMenuConfig(component, !component.menu));

                } else if (component.isXType('buttongroup')) {
                    items = component.items.items;
                    iLen  = items.length;

                    for (i = 0; i < iLen; i++) {
                        me.addComponentToMenu(menu, items[i]);
                    }
                } else {
                    component.overflowClone = menu.add(Ext.create(Ext.getClassName(component), me.createMenuConfig(component)));
                }
            }
        },

        /**
         * @private
         * Deletes the sub-menu of each item in the expander menu. Submenus are created for items such as
         * splitbuttons and buttongroups, where the Toolbar item cannot be represented by a single menu item
         */
        clearMenu : function() {
            var menu = this.menu,
                items, i, iLen, item;

            if (menu && menu.items) {
                items = menu.items.items;
                iLen  = items.length;

                for (i = 0; i < iLen; i++) {
                    item = items[i];
                    if (item.setMenu) {
                        item.setMenu(null);
                    }
                }
            }
        },

        /**
         * @private
         */
        destroy: function() {
            var trigger = this.menuTrigger;

            if (trigger && !this.layout.owner.items.contains(trigger)) {
                // Ensure we delete the ownerCt if it's not in the items
                // so we don't get spurious container remove warnings.
                delete trigger.ownerCt;
            }
            Ext.destroy(this.menu, trigger);
        }
    });