i just realized that "pinch to zoom" is working with my chromebook which has an intel Celeron CPU. But it is nor working with my chromebooks which have a MediaTek CPU. Could the CPU be the problem ?
sorry for replying so late. my touchscreen works of course perfectly. it also used to work with the windy website but not any more. e.g. "pinch to zoom" just works fine with the google earth website. i'm using chromebooks.