If you die and then press F11, the menu buttons are disabled, so you cannot respawn or return to the main menu. The only way to get out of this situation is to close Minecraft completely.
MC-1071
Upon death, menu buttons disabled at F11
Resolved
Duplicate
0
Adam Decker
(Unassigned)
Unconfirmed
death, fullscreen
Minecraft 1.4.2
Retrieved
This ticket has been marked as a duplicate of MC-2835 , in favor of the better description/information provided.