Lost Ctrl+Shift+hex unicode entry - FC6 issue?

[Neil Bird]

   At some point in the recent past, I seem to have lost the ability to 
enter Unicode values in GTK apps. (inc. Thunderbird & gvim) by holding 
<Ctrl+Shift> and entering the hex value.  It seems to act as if <Shift>'s 
not held down (and yes, my Shift keys work).

   This may have happened as part of upgrading from FC5 to 6;  anyone any 
idea what to check?

-- 
[neil at fnx ~]# rm -f .signature
[neil at fnx ~]# ls -l .signature
ls: .signature: No such file or directory
[neil at fnx ~]# exit