How to enable impress presenter-console?

I am trying to get the presenter-console working on my Ubuntu 15.04 Notebook. There is an external Display hooked up to it via VGA in extended mode:

Here are my slide-show settings in Impress:

When I start the presentation, the presenter-console does not show up.

I tried rearranging the displays, so the external monitor is on the right. Also, I tried this OpenOffice add-on.

However, none of these methods worked.

Do you know how I can enable the presenter-console?