Very odd key event behavior in trunk

[John Wiegley]

I haven't yet been able to track this down to a reproducible case, but I'm 
using the latest trunk on OS X 10.6.3, built using "--with-ns".

What happens is that Emacs will suddenly start misinterpreting my keystrokes.  
For example, I have C-RET bound to `other-window', so I press that quite often. 
 Then, for no reason I can determine, Emacs suddenly thinks that I'm typing C-\ 
<tab> whenever I type C-RET.

If I switch away from Emacs with Cmd-TAB and switch back a few times, it seems 
to reset this problem, but until I do switch away Emacs thinks that every C-RET 
is a C-\ <tab>.  Nor is this is the only key sequence that gets misunderstood.  
The only thing in common between the misinterpreted keys is that they all use 
modifiers of some kind.

Has anyone else seen this very odd behavior?  With the same .emacs 
configuration I never once saw such a thing Emacs 23.

John