pointer grabs should time out

[Mike Hearn]

> An idle tcp link can take two hours or more to time out. Grab breaking
> makes sense as a keypress, 

Domain socket connections should break instantly though, right? It'd be 
nice if the X server did detect this: I too have had problems with 
having to manually kill apps that "froze" the system.

Another approach would be to have the WM break grabs if the grabbing 
client advertisises support for the EWMH PING protocol, much like the WM 
can currently detect hung applications which participate.

Problem with that is, that I guess the ping messages are blocked by the 
grab as well :)

thanks -mike