code: function() {
  
  		if (!this._mouseover_stack_changed_listener) {
  			Lava.view_manager.lendEvent('mouse_events');
  			this._mouseover_stack_changed_listener = Lava.view_manager.on('mouseover_stack_changed', this._onMouseoverStackChanged, this);
  			if (!this._tooltip) this._tooltip = Lava.createWidget(this.DEFAULT_TOOLTIP_WIDGET);
  			this._tooltip.inject(document.body, 'Bottom');
  		}
  
  	}
docs: Create tooltip widget instance and start listening to mouse events