kivy/kivy — pull request #2808 by inclement (2014-12-31 16:33:05+00:00)
Title: Sdl2 scroll fix

This resolves https://github.com/kivy/kivy/issues/2807

The problem seems to occur partly because sdl2 treats the scroll event differently to a touch. In pygame, the _mouse_x and _mouse_y are set in the mouse down event handler, but with sdl2 the scroll event doesn't receive the mouse position as input. I couldn't think of a better fix than setting it on every mouse move.