If I make a reservation in the back, I can not select an object. In the overview of reservations is always only "No subject reserved" and the rest of the table row is moved, as if a column is missing.
Is this a bug or ...?

Hello,

We know about this problem and it should be solved for next release. I am not sure if it will be repaired that you will be able to create new reservations via backend, but there should be probably 1 way for administrators to make reservations.