If we get two configure events on the root window in close
sequence, then we could get the sequence:
ConfigureNotify on the root window w1xh1
Processed by Mutter
clutter_actor_set_size(stage, w1, h1)
<relayout happens, stage window resized by clutter>
ConfigureNotify on the root window, w2xh2
Processed by Mutter
clutter_actor_set_size(stage, w2, h2)
ConfigureNotify on the stage window, w1, h1)
Processed by Clutter
clutter_actor_set_size(stage, w1, h1)
<relayout happens, stage window resized by clutter>
Leaving the stage at the wrong size. To avoid fighting with Clutter,
switch to resizing the stage with XResizeWindow(), similar to how a
toplevel window is handled by a window manager.