I have build a Watch face (GVWatch) that can only update on screen what has been changed. This can reduce battery power even more because drawing is reduced to a minimum. In the sumilator it works perfect but when I test it on my own device the first second it looks okay but then only the parts that are changes are visible. It would be nice if the simulator would work the same and even better: the watch screen is not cleared before the Watchface OnUpdate() is called so the watch only updates what is changed :)
Is there a general reason for this last behavior or could this be something that could work?