I have similar symptoms with debian stretch and latest testing updates installed. My X starts to freeze, i can close windows but not do anything else. Opening a menu stays on the screen and if I type sudo reboot to the xfceterminal, nothing happens. I need to reboot to solve the situation, ctrl+alt+f1 or ssh does not work.
So far gEdit works better. It is funny that text editor hangs my machine but Tomb Raider 2013 windows game works fine.
