Thank you both! It has taken me quite a few hours, too. I did make my windows aware of the xTab, because I want all tabbed windows to handle their own scaling and centering etc, thus a need to know about their container. However, it was pretty easy to avoid using the VI-reference-ownership-transferring property nodes. Problem solved. It is however something that Olivier may want to address in the documentation of the toolkit.
Aart-Jan
