Strange behaviour of guidelines

Sometimes, only in some layers, (new created and old) guides are not selectable. I can delete them, lock them and convert them via context menu. And I can double click to ratate them. But I can not select them or drag them.
It seems to be caused by a plug-in. But which one? Any hint?

Never heard of it.

Does it help to re-open the file?

No.
I have deactivated “selection palette” and “simple preview” in a first test. And it seems to be gone. I will keep an eye on it…