[seabee]

Using message queue semantics to implement Java-style OOP is the kind of thing that would put Alan Kay into a rage.

The failing of the Windows message system is not distinguishing between the 'command' messages that you are allowed to send to a window to effect some action (WM_NOTIFY and friends) and the 'event' messages caused by the window manager (WM_DESTROY, input events etc.). It should be apparent that getting a window to respond to an event is not the same thing as effecting that event.

Crucially, OOP languages without access modifiers (or ones you can #define away, like C++) have this same problem. If an ignorant programmer thinks he can destroy a window by calling its _onDestroy() function, you have solved nothing.

With sufficient language support you can probably save users from themselves in this case, but there are many other cases where a user can do the wrong thing by not understanding the system. At some point the effort doesn't justify itself.