For some days now I had freezes and problems (e.g. I had to refresh the
workspace by switching back and forth to bring the user interface up to
date) with Gnome GTK applications like gnome-terminal or nautilus when
using xmonad without a loaded gnome-session (plain xmonad). I noticed,
that this was due to an old setting in the xmonad configuration file:

myStartupHook = setWMName "LG3D".

I added this settings years ago to get Java applications to work. After
several hours of trial and error I removed this line and the glitches
and freezes vanished. I thought, that I should comment this here.