@Ingmar, Yes, I’m on the latest build and my original issue was solved by upgrading. I can edit the field group name without problem, but the issue with åäöÅÄÖ still remains.
As you say I get the “standard” error message as you can see below, when I try to use åäöÅÄÖ in field group name. Now I’ve just chosen names with out those characters.
An Error Was Encountered
The name you submitted may only contain alpha-numeric characters, spaces, underscores, and dashes
This is the first time we build an EE site using Swedish inside the control panel. Handling Swedish in entries and such is rarely a problem and we use UTF8 everywhere.