Thierry de Coulon wrote:

> What I don't know is what is causing the problem. The rest of the keyboard
> layout continues to work, only Alt Gr is gone. So far only loging out and
> in cures the problem.

This is strange as I never had a problem with the keyboard. I have
DE,US,BG,RU at home and DE,CH,US,BG in the office.

I use jessie with TDE 14.0.2

What debian version do you have and what TDE?

Perhaps you should check the settings - example disable external xkb or
alike.

German - nodeadkeys ... for CH I don't know which variant is setup  ATM.

If its not a setting, it could software defect for the keyboard model (did
you try with another one) or even a hardware defect.

regards