Comment 34 for bug 949791

Some more info on what was going on:

Nautilus, the file manager, is in charge of the desktop. This is how files on your desktop are managed. When it sees button press event, it grabs the device. When the button release event is seen, it ungrabs the device.

GTK is only selecting for events on master devices, but if it sees an event on a slave device it will interpret the event as though it came from a master device. The bugs in the X server were generating both master and slave button press events.

Slave and master events are delivered independently. The master button presses were being sent correctly to other windows that the user touched. The slave button presses were being sent only to Nautilus due to the X bug. This was causing nautilus to grab the master device, so all further events were being directed to it instead of to other windows.