I just notice today that i cannot do the drag and drop action with my laptop touchscreen when playing live chess game at chess.com. I've looking the net for some solution but failed to find one.
For your information, I was using latest Mozilla Firefox. When using google Chrome, did not encounter this problem.
So, I went to look at Mozilla Firefox configuration, at about:config that will give out this kind of warning:
I went to click "I accept the risk" and searching for touch_event, and my screen looked like this:
I doubled click the key named "dom.w3c_touch_events.legacy_apis.enabled" so the value went from false to true.
When I open a new live game at chess.com, the drag and drop has worked once more.
I hoped this log help anyone.
