[PLATFORM REG]: pinchzoom: mice do not animate unless multitouch events are generated

When running the pinchzoom example on Windows 7 (on a Dell Latitude XT2), the mice do not animate unless multitouch events are generated, i.e. two fingers have to touch the screen in order for the mice to animate.

This problem does not occur on Mac, where the mice are animated even when the user does not generate multitouch events.