I am receiving other types of messages, so I know the overloaded method is being called.
The only info I have found from searching talks about needing to give my Panel focus so that it can receive inputs. However, that solution did not help anything. (http://www.dotnet247.com/247reference/msgs/44/221762.aspx)
Any help would be appreciated :)
So the problem was related to the Panel not having focus.
A Panel (and some other types of controls) can not receive certain types of inputs because it can not receive proper focus.
I just changed the type from a Panel to a Button and things worked.
This was acceptable for me since I am only using this control as a tick/render surface anyways.