Comment 12 for bug 769644

> Anyone here who knows how to debug X11 events?

One useful tool for debugging X events is xev. You can tell it to display all events seen by a window by doing

  xwininfo

to get the Window ID, and then

  xev -id WINDOWID

will get you information about every window event that window sees. I am less sure about using xev on a root window, but... you can try it :) So, something like:

  xev -id $(xwininfo -root |grep id: |cut -d " " -f4)

should get you what you need.