function createMouseMoveEventMerger(mouseTargetFactory) {
        return function (lastEvent, currentEvent) {
            var targetIsWidget = false;
            if (mouseTargetFactory) {
                targetIsWidget = mouseTargetFactory.mouseTargetIsWidget(currentEvent);
            }
            if (!targetIsWidget) {
                currentEvent.preventDefault();
            }
            return currentEvent;
        };
    }
Merges mouse events when mouse move events are throttled