This is absolutely a great answer to my question!
Of course, unfortunately the answer is "It can't be done". But, to be honest, I already had a vague suspicion though. And now I finally know that, so it has been confirmed. Further, your explanation about the underlying structure and sort of theoretical lesson was quite informative. My knowledge has grown somewhat more.
The alternative way you are suggesting is also very useful. I think that is indeed a good workaround or especially an alternative way of presenting things. And the tip concerning the use of sub-Panels was also new for me. Not that it comes into hand for this application, but good to know for future use.
Again, thanks a lot and very much appreciated!!
Kind regards,
DvdM