We got the problem that it is not possible to create a subtask for a Task. 
As you can see i can see the Button for creating a subtask but if i click it only this line appears
When i click on Erstellen (create) nothing happens. In Other projects the create window appears like it should.
i've compared the settings for both projects side by side but i could not figure out any difference
here is also a screenshot of the configured screens
It looks exactly like in the other projects. What am I missing here?
