I created a new single player, creative map (with unicode characters in name, if it matters), flew up a bit to get a good overview, opened the menu and switched window to let the world generate for a while. Upon switching back, closing the menu grabbed the mouse and froze the game, when trying to get response by by pressing buttons, moving mouse and trying to switch window again, nothing happened until a while later when the crash screen appeared and mouse input was released.
Crash report attached