doLayout issue in Ext.menu.Menu

[ZooKeeper]

It worked in ExtJS 4.0.7, but was broken in 4.1.3 and is still broken in 4.2

tb.add({
        icon: 'preview.png',
        cls: 'x-btn-text-icon',
        text: 'Scrolling Menu',
        menu: scrollMenu
    }); 

to:
1st test case:

   // scrollable menu
    var btn = tb.add({
        icon: 'preview.png',
        cls: 'x-btn-text-icon',
        text: 'Scrolling Menu',
        menu: scrollMenu
    });
    setTimeout(function() {
        btn.showMenu();
    }, 1000);
    setTimeout(function() {
        scrollMenu.removeAll();
        scrollMenu.add({ text: 'test item' });
        scrollMenu.doLayout();
    }, 3000); 

In this test case you will see full menu after 1 sec. and "detached" item after 3 secs. which will be at top (where first menu item of full menu was)
2st test case:

    // scrollable menu
    var btn = tb.add({
        icon: 'preview.png',
        cls: 'x-btn-text-icon',
        text: 'Scrolling Menu',
        menu: scrollMenu
    });
    setTimeout(function() {
        btn.showMenu();
    }, 1000);
    setTimeout(function() {
        scrollMenu.doLayout();
    }, 3000); 

In this test case scrollers will be disappeared

I think it's some troubles with menu height and shrinkWrap property of its layout.

First snippet effect:

2013-03-20_22-37-07.png

Second snippet effect:

2013-03-20_22-39-47.jpg

Supposed to be like this:

2013-03-20_22-40-53.png

[evant]

I don't really see a problem here. The menu positions itself when it's triggered by the button. When you add new items and trigger a layout, you're asking the menu to do something independently.

If you want the menu to reposition, then hide it and show it again.

var btn = tb.add({ 
        icon: 'preview.png', 
        cls: 'x-btn-text-icon', 
        text: 'Scrolling Menu', 
        menu: scrollMenu 
    }); 
    setTimeout(function() { 
        btn.showMenu(); 
    }, 1000); 
    setTimeout(function() { 
        btn.hideMenu();
        scrollMenu.removeAll(); 
        scrollMenu.add({ text: 'test item' });
        btn.showMenu(); 
    }, 3000);

[ZooKeeper]

It's very slow in long menus. In ExtJS 2 you can easily add and remove items without hiding and showing menu after. You can to do it in 4.0 too. Why can't I to do it in 4.2?