Here is the story:
I got this to work without tests, since I just can't think of how to test this stuff. Right now I'm heavily using the functionality that Netron provides (which does 96% of the above) and the implementation uses windows events and state tracking quite heavily to get this functionality.
I suppose I can try to refactor the logic out so it would be testable, but that would mean duplicating the events structure for WinForms. In addition, I can see no way to test that the correct stuff is drawn to the screen and I am not fond of taking a screen shot and then comparing the known good to the result on a bit by bit basis. If for no other reason than that I can think of several dozens of tests for the functionality that I need.
Any suggestions on how to test this?