SOLVED
On the console do the umlauts, but not in X. äöü... keys are dead.
I am switching between de and th keyboard ($ setxbkmap de,th)
Wattos R8 lxde gives my old Asus EEEPC 701 a new life
running fast and stable!
After a new installation everything works fine. Maybe a package i installed for Thai-Support was the cause...
