Hello Thomas,

It has been a while since you have made your post, in case you still need support I will be glad to assist you further. I suppose the other community members can benefit from this answer as well. I have been looking through your post and I created a sample project for you in which I implement the functionality you want. Basically I handled the Window’s SizeChanged event and set the SelectedNode’s Width to a proper value to fi the Window.

Feel free to write me if you have further questions.