code: function(view_manager, stack) {
  
  		var new_tooltip_target = null,
  			html;
  
  		for (var i = 0, count = stack.length; i < count; i++) {
  
  			if (Firestorm.Element.hasAttribute(stack[i], this._attribute_name)) {
  
  				new_tooltip_target = stack[i];
  				break;
  
  			}
  
  		}
  
  		if (new_tooltip_target != this._tooltip_target) {
  
  			if (!this._tooltip_target) { // if there was no tooltip
  
  				if (Lava.schema.DEBUG && this._mousemove_listener) Lava.t();
  				this._mousemove_listener = Lava.Core.addGlobalHandler('mousemove', this._onMouseMove, this);
  				this._tooltip.set('is_visible', true);
  
  			} else if (!new_tooltip_target) { // if there was a tooltip, and now it should be hidden
  
  				Lava.Core.removeGlobalHandler(this._mousemove_listener);
  				this._mousemove_listener = null;
  				this._tooltip.set('is_visible', false);
  
  			}
  
  			if (new_tooltip_target) {
  
  				html = Firestorm.Element.getAttribute(new_tooltip_target, this._attribute_name).replace(/\r?\n/g, '<br/>');
  				this._tooltip.set('html', html);
  				this._tooltip.set('is_visible', !!(html || !Lava.schema.popover_manager.HIDE_EMPTY_TOOLTIPS));
  
  			}
  
  			this._tooltip_target = new_tooltip_target;
  
  		}
  
  	}
docs: Mouse has crossed an element boundary. Find new element with tooltip and show new content
  @param {Lava.system.ViewManager} view_manager
  @param {Array.<HTMLElement>} stack