CAE issues

During some experiments in creating a Composite with the PIM component Contacts View, I kept running into issues with the Composite Application Editor. In many cases when I open my composite app, the editor does no longer allow any input. So for example I can select Rename Page, but I cannot type in any value.

When I close the CAE also my Standard client shows strange behaviour, like I have to double-click (instead of single-click)on tabbed pages.

Anyone any idea, what’s causing this??