Keygrabbing not working for some keysyms

[Pierre Ossman]

I'm having problems with key events not reaching the application that
has grabbed the keysym. I don't know where to start digging so I need
some help.

The problem is that taking screenshots do not work for me. After
debugging metacity for a few hours I concluded that the problem was more
fundamental, metacity never got events for the keysym Print. I verified
this with another program (xbindkeys) to make sure I hadn't
misinterpreted things.

What I've concluded so far:

 * Grabbing the key works as intended. I.e. only one application can
have the key grabbed at a time.

 * The key event is sent, but to the current application, not to the one
who has grabbed it.

 * The problem is keysym specific. So far I've only found one sym, Print.

Even if you don't have the time to debug this yourself, please give me
some ideas on where the problem might be since I have no idea where to
start.

Rgds
Pierre