code: function hideTooltipOnMouseMove(e) {
  			var pageX = defined(e.pageX) ? e.pageX : e.page.x, // In mootools the event is wrapped and the page x/y position is named e.page.x
  				pageY = defined(e.pageX) ? e.pageY : e.page.y; // Ref: http://mootools.net/docs/core/Types/DOMEvent
  
  			if (chartPosition &&
  					!isInsidePlot(pageX - chartPosition.left - plotLeft,
  						pageY - chartPosition.top - plotTop)) {
  				resetTracker();
  			}
  		}
docs: Special handler for mouse move that will hide the tooltip when the mouse leaves the plotarea.