I can’t really get behind this bug. I can’t rotate anything anymore. No matter if it’s a final build glyph in a existing file or if I am opening a new file and just want to rotate a square for example. I’m also updated to the latest version of glyphs.
Anyone maybe with the same issue, or any clue how to fix that?
Thank you guys in advance!
How are you trying to rotate? With the rotate tool (R)? Or with the rotation button in the transformations panel?
@SCarewe I always used the rotation button in the transformation panel. And it stopped working from one day to the other. Strange!
But thanks for your reply. With the rotate tool (R) it still works. 
At least I can use this option though, thank you!
Also the tool to mirror objects/glyphs doesn’t work anymore… Would be really helpful if someone has a clue where this could come from!?
I think it’s because you changed accidently this :
(the transformation origin, the dot in blue)
thank you Hugo! Could have solved this on my own. 