RangeError inside mx.controls::Menu/show()

Question

This bug seems to happen only with submenus, when the mouse
move quickly on another menu.
the Hide/Show part of the MenuBar seems to be buggy.
How to reproduce it ? this is not very clear. see in the end
of this POST.
RangeError: Error #2006: L'index indiqué sort des
limites.
at flash.display::DisplayObjectContainer/addChildAt()
at mx.managers::SystemManager/
http://www.adobe.com/2006/flex/mx/internal::rawChildren_addChildAt()[C:\dev\GMC\sdk\framew orks\mx\managers\SystemManager.as:1578
at
mx.managers::SystemManager/addChild()[C:\dev\GMC\sdk\frameworks\mx\managers\SystemManager .as:1190]
at
mx.managers::PopUpManager$/addPopUp()[C:\dev\GMC\sdk\frameworks\mx\managers\PopUpManager. as:221]
at
mx.controls::Menu/show()[C:\dev\GMC\sdk\frameworks\mx\controls\Menu.as:1027]
at
mx.controls::MenuBar/mx.controls:MenuBar::showMenu()[C:\dev\GMC\sdk\frameworks\mx\control s\MenuBar.as:1350]
at
mx.controls::MenuBar/mx.controls:MenuBar::mouseOverHandler()[C:\dev\GMC\sdk\frameworks\mx \controls\MenuBar.as:1431]
I build the MenuBar example in the offical Doc.
<menuitem label="Menu1">
<menuitem label="MenuItem 1-A" data="1A"/>
<menuitem label="MenuItem 1-B" data="1B"/>
</menuitem>
<menuitem label="Menu2">
<menuitem label="MenuItem 2-A" type="check"
data="2A"/>
<menuitem type="separator" />
<menuitem label="MenuItem 2-B" >
<menuitem label="SubMenuItem 3-A" type="radio"
groupName="one" data="3A"/>
<menuitem label="SubMenuItem 3-B" type="radio"
groupName="one" data="3B"/>
</menuitem>
</menuitem>
then I click on the menu to activate it.
then I move the mouse quickly a circular way over the menubar
the trick is to move over the "SubMenuItem 3-B" and go as
fast as you can
on the first menu: "Menu1"
doing this will crash after 10 seconds (depend where the
mouse move)
it seems that the submenu is not properly closed, or its
parent menu is dead before him...

Answer 1

to be more precise, it is certainly related to SUBMENU.
nothing happen with simple 1 level menu.
so troubles should begin with items "SubMenuItem 3-A" and
"SubMenuItem 3-B" when mouse
move over them quickly to another menu, for example "Menu1"
then go back to the parent of the
submenu ("Menu2").
show() crash to display "Menu2", may be because submenu is
not properly closed.