Full redraw of root window

[Ian King <king eiffel com>]

Hi,

Is is possible for gtk to force a redraw of the entire root window.  
With gnome 2.10 on Fedora Core at least, when I draw to the root window 
using gdk_draw_line with the drawable being the gdk_root_parent, a call to

          gdk_window_invalidate_rect (gdk_root_parent, default_pointer, 
True)
          gdk_window_process_updates (gdk_root_parent, True)

does not remove the line, is there a way I can force the root window to 
redraw itself and all of its children and therefore remove any drawings 
that I have drawn using gdk_root_parent.

Thanks for your time

Ian King