I have a little problem here.
All our nodes are fitting in the visible diagram, but if they come to close (estimated 10 Pixels) to the border the diagram is showing a scrollbar.
So i think the needed size is not calculated well.
I remember to have that problem with the standard wpf TabControl also - there I calculate the needed space by myself and set the scrollbar visibility to false, even if the control wants to show them.
Do you have a hint, or a method to do this in diagram also - with account to zoom and pan?