Most of the time I can't copy/paste Text anymore. Neither via right mouse -> Copy/Paste nor via Ctrl+C/V. The result of copying from gedit "Test1234" and pasting it back into gedit is "°ö". But the resulting 4-char Strings vary from time to time. The only copy/paste variant that seems to work correctly all the time is the Middle-Mouse copy in terminal. The applications I tested are: gedit, terminal, firefox, eclipse In all of those the problem was there.
Locales are set to _en_GB.uft8_ (dunno whether this is relevant).
The strangest thing is, that there are short moments copy/paste works just fine.
Thanks a lot for your help in advance!