It was much easier to subclass a control and modify its behaviour by altering the handling of certain messages for that control than creating a brand new contro

It was much easier to subclass a control and modify its behaviour by altering the handling of certain messages for that control than creating a brand new control and trying to mimic every behaviour to every Windows message sent. The Spy (or was it Spy++) app from the Windows SDK was very useful to figure out the best place to subclass the control, along with logging Windows messages and params sent to your subclassed control's WndProc.