WinXP 2002080208 Dropdowns, including menus and personal toolbars, have a drop shadow. The java news ticker at http://www.manchesteronline.co.uk/today/ causes the drop shadows in ALL mozilla windows (even ones showing other pages) to flicker. The applet at http://java.sun.com/openstudio/applets/quote.html also causes a slight, but much less noticable, flicker.
==> default owner
After some poking around, these drop shadows are a Windows XP feature, not mozilla. So it's debatable how much mozilla can do...
Now works fine, Moz 1.3b, JRE 1.4.1_01 -> WFM