Avoid DocumentChanged when ports are displayed OnM

I use view.DocumentChanged to notify a form about changes in my diagram.

My problem now is, that the document changes if the mouse hovers over a node. The ports’s SkipsUndoManager property is set to true Cry

 public override bool OnMouseOver(GoInputEventArgs evt, GoView view) {
            if (view != null && ! (view is WorkflowPalette)) {
                foreach (GoPort p in Ports) {
                    p.SkipsUndoManager = true;
                    p.Style = GoPortStyle.Rectangle;
                    p.Brush = null;
                    p.SkipsUndoManager = false;
            return false;

OK, I combine this with the view’s IsModified property.
That allows even to react on an undo …

SkipsUndo simply skips recording the document changes in the Undo list, it doesn’t prevent the DocumentChanged from happening. You can look at the hint and object in the GoChangedEventArgs arg to see if it is the port changing in the DocumentChanged event.