Preventing Events from being clobbered by WM's

[Pete Collins <pete mozdev org>]

I have a requirement for some gtk2 code i'm working on to block WM key 
bindings like ALT+TAB, CTL+K, etc.

I also need to block CTL+ALT+BACKSPACE which is an event controlled by 
the X server i believe.

Can I do this from the application window widget using gtk, gdk or even 
xlib?

Thanks in advance.

--pete