Created attachment 3780 Example Video xfce4-terminal, edit, preferences, general, scrollbar is:, *select any option* This caused my focused preferences window to disappear under the rendering of the terminal window behind it. Also the panel with my menu items all went black. I have compositing off. I'm using Ubuntu 11.04. Feel free to send me questions. Here is an example video: http://tinypic.com/r/k1tmas/7 I used xvidcap and I believe it artificially made the panel distortion less impressive, but the panel stays at least partially affected until I switch workspaces. Mousing over items rids some of the distortion.
I also noticed when submitting this bug that the Version combo-box doesn't contain a 4.8 option which is my XFCE version.
Terminal follows a different version scheme (see about dialog). Most of the time issues like this are caused by video drivers or the window manager. Try metacity instead of xfwm4, gnome-terminal (which is another vte terminal emulator) and last but not least the latest video driver (esp. recent nvidia drivers have seen some problems).
This is then resolved for me, with too many possible causes and plenty of work-a-rounds. Also, my version of terminal is 0.4.7 while the version combo box only goes to 0.4.5 when creating bug reports.