Ok, in my simple pong game I allow the user to use the mouse as a method of input. I simply use player.y = HIWORD(lParam). My program also has a menu and when accessing the menu, I think it generates a WM_MOUSEMOVE message. This causes player.y to use the new y-coordinate. It also happens when using the keyboard to access the menu. How do I ignore a WM_MOUSEMOVE message when it is generated by a menu?