I have a DiagramPanel that is the main working canvas in the view. On the bottom right side of the view is a smaller view containing an Overview of the DiagramPanel. Bound to the DiagramPanel Scale property is a Slider. The slider is used to zoom in and out the DiagramPanel. For the most part this is working very well. There is a defined area on the DiagramPanel that placement of nodes is valid (basically a rectangle 0,0,1000,1000), which I set Diagram.Panel.FixedBounds to.
When I set a Border on the DiagramPanel it adds the border around the entire DiagramPanel including the scrollbars when zoomed out to see an area larger than I want as a defined as the fixed bounds.
I have code in the ViewModel to restrict placement outside of the defined bounds, but what I have not been able to find is a way to draw the border so the users have a visual indication of valid area where nodes can be placed when the view is zoomed out.