Hello Lutz,
I don't know which keytable you use, but in my german keytable is the same problem.
You can solve the problem, when you edit your own keytable.
- open mc (Midnight Commander) and move to '/home/root/Applications/cyrillica'.
- select your favorit language
- press <alt> + <4> for edit
- insert in the section [keyboard] following line
'?' '?' '.'
- press <alt> + <2> for save and confirm with [save]
- after that you have to reset your languagerelations
-- start ->Settings->Keyboard
-- press <OK>
(careful, for german there are two keymaps, edit the 'deutsch'-keymap, it ist the better-one)
that's all
I hope that'll solve your problem
regards
curiosity