Hi! I have been fiddling around with one of your samples: WinFormsExtendedViewExample I have noticed that the view control contains a disposable member: graphicsHelper. I was sad to see that disposing it throws an ArgumentException: After a bit of thinking I figured out the reason. GraphicsHelper constructor initializes the backing fields of DefaultPen and DottedPen to newly created pen objects. The backing field of HighlightPen however stay at its default value: Pens.Green. This is an immutable system pen and thus, non-disposable. Trying to dispose it will throw the above mentioned exception. Am I right in saying that this is a bug? I can temporarily fix this by overriding all the system pens/brushes/fonts used in GraphicsHelper before disposing it, but it's a sloppy workaround. I am using CadLib version 4.0.38.118

Good catch, I've updated the release and trial versions. Pity you can't check if a Pen/Brush is immutable, so now the code calls Dispose() and just catches the ArgumentException. - Wout

Thanks! Will check!