and then released over that
menubutton, the menubutton stays posted: you can still move the mouse
over the menu and click button 1 on an entry to invoke it.
Once a menu entry has been invoked, the menubutton unposts itself.
<P><LI value="4">
If button 1 is pressed over a menubutton and then dragged over some
other menubutton, the original menubutton unposts itself and the
new menubutton posts.
<P><LI value="5">
If button 1 is pressed over a menubutton and released outside
any menubutton or menu, the menubut