Subclassing a window and not getting all the messages

[Dave Calkins]

We're interested in subclassing a window in order to handle window messages (specifically mouse click and movement). Our current approach is to derive a listener class from NativeWindow, assign it the handle to the window in question, and then set up a message handler to handle the incoming messages. The behavior we’re seeing is that only a very few windows messages come down to our listener class. (Mainly WM_NCHITTTEST). Any ideas?