In my favorite text editor on a Windows XP box I use the shortcut ALT ö (= german umlaut ö)
As soon as I launch k-Meleon, it does not work anymore, after closing KM it works again. 100% reproduceably. Other shortcuts, even Alt ä, are fine.
In KM, ALT ö does not seem do have any effect.
Vanilla accel.cfg of course.