I'm guessing the app creates a transparent NSWindow the size of the screen, and you are drawing to that. That's why scrolling doesn't work. In order for scroll

I'm guessing the app creates a transparent NSWindow the size of the screen, and you are drawing to that. That's why scrolling doesn't work. In order for scrolling to work you'd have to do something like create a transparent window over the app you are drawing on, and scroll the application window that is below using the Accessibility API.