If open the popup menu on the input box and select
Input Method -> X Input Method, key bindings for Alt+1
... Alt+9 stop working (instead of switching between
tabs they enter digits in the input box).
The reason is that the gtk input module interprets
these keystrokes and xchat's key_handle_key_pressAFTER
never sees them.
I propose to fix it by getting rid of
key_handle_key_pressAFTER and doing all the processing
See http://bugs.debian.org/188862 for more information.