Comment 4 for bug 993624

OpenTTD has little to no control over what the window does when it's resized. This is all left to SDL. The only thing OpenTTD has to worry about is painting the game's graphics within the window. In case of full screen there is a window without decorations spanning the complete screen.

Thus I think this is not a bug in OpenTTD, but rather in SDL or some library SDL uses. So it should be possible to reproduce this behaviour with other SDL applications as well.