Changing state does not work correctly on Properties -view

1. Create a new 3D project
2. Create new state from State -view. You can name it "Test"
3. Save project
4. Select cubeModel from Navigator
5. Open Properties -view and try to change 'base state' to 'Test'

User cannot change the state. Only when user:
1. Closes and opens the project again
2. Selects "Test" state from States -view

then State -combobox starts working correctly in the Properties -view

Also this affect State Groups in State -view. If user wants to select some states from state groups, they cannot do that in Properties -view.