Story #11939: As a user I want to have a clean UI
Model can be dragged out of the usable area in the Domain Modeling
Steps to reproduce:
1. Go to the Extbase Kickstarter BE module.
2. In the drop-down, select "Domain Modelling".
3. Drag the "New Model Object" to create a new model.
4. Drag the model up (above the upper border of the "Domain Modeling" box).
Either the model cannot be dragged out of the box, or the box' scroll bar allows to scroll to the model.
The model now is out of the box and cannot be dragged back (or be used), rendering it useless (see screenshot).