Add Dropdown menu atoms so we can add shadows to them. Fixes #517442

2008-05-24  Iain Holmes  <iain@gnome.org>

        * src/compositor/compositor-xrender.c: Add Dropdown menu atoms 
so we
        can add shadows to them. Fixes #517442
        Handle tooltips as well. Fixes #517524


svn path=/trunk/; revision=3725