I have a 100% repro for this bug, and this bug will slaughter my new game because I encourage fullscreen.
Steps:
[ol]
[li]Enter game. F11 (fullscreen)[/li]
[li]Teleport to another place in the universe[/li]
[li]Try to exit fullscreen (F11)[/li]
[li]Client crashes[/li]
[/ol]
Basically your screen is stuck white and unresponsive.