OnHover event multiple firing

I created a class that inherits the GoNodeIcon. I added an override function for the OnHover event. The event fires as expected when the cursor is over the icon allowing for a tooltip to be presented.
However....after resizing the form (dragging larger, or maximize), the next time the cursor is over one of the GoNodeIcon objects, the tooltip for all GoNodeIcon(s) on the diagram are displayed, one on top of the next where the cursor is positioned.
Any ideas on what may be causing this? Any ideas on preventing it?

No idea, never saw that before. Can you reproduce with any of our samples?