I have a combobox in a window, and I’m running this on OS X. When I
on the dialog button to drop it down, the toplevel that displays the
behind the window (in this instance, the root window), and I have to
on the overhanging part to make it come forward. This can be an issue
users when there is no overhang, however (as they may not know that just
moving the window containing the combobox will reveal the list window).