code: function() {
  			lib.returnFocus(this._wrapperNode, this._previousActiveElement);
  			this._previousActiveElement = null;
  
  			this._wrapperNode.classList.remove("slideoutWrapperVisible"); //$NON-NLS-0$
  			
  			this._wrapperNode.classList.add("slideoutWrapperHiding"); //$NON-NLS-0$
  			this._visibilityTransitionTimeout = window.setTimeout(function() {
  				this._visibilityTransitionTimeout = null;
  				this._wrapperNode.classList.remove("slideoutWrapperHiding"); //$NON-NLS-0$
  			}.bind(this), VISIBILITY_TRANSITION_MS);
  		}
docs: Hides the slideout.