Can't Edit events with attendees

When creating en event from scratch, everythings works OK. I can modify and change its contents normally.

But if I add attendees or, by the way, the even was created from an email, the event is not editable anymore. I only can “move” it by draging, but I cannot modify for instance the location, notes, or anything.

Attached yoy’ll find the minimum dialog tha I can access in this situation, but as stated above, I cannot modify enything. Only deletion is possible.

this has been already reported to us. I will discuss it with our developers and will try to provide a solution as soon as possible.