This issue is tested on 3.1.4.GA and now on 3.2.1.GA as well.

It works on Firefox, but not on IE 6.0.2900

excerpt:

<rich:toolBar>
 <rich:toolBarGroup>
 <s:link/>
 <s:link/>
 <rich:dropDownMenu styleClass="menu_item">
 <rich:menuGroup>
 <rich:menuItem/>
 </rich:menuGroup>
 </rich:dropDownMenu>
 </rich:toolBarGroup>
</rich:toolBar>

Below that menu within a div I have some rich:panels et.al.

On Firefox, the dropDownMenu is shown above the panels.
But on IE, the panels or even normal text is over the dropDownMenu.

.menu_item *{
 z-index:100;
 position: relative;

}

Has anybody seen that as well?