Right now message handlers need to locate the instance by the window handle they were sent to. This library should feature a OnGUIMessage(Message, Function) method that enables message handling of this message and forwards it to GUI.Function.
Implemented. There might be issues with ShellMessage being handled through this mechanism and with users calling OnMessage to override the callback function used here, but other than that it should be fine.
Right now message handlers need to locate the instance by the window handle they were sent to. This library should feature a OnGUIMessage(Message, Function) method that enables message handling of this message and forwards it to GUI.Function.