code: function(restoreFocus) {
  			var actionTaken = false;
  			if (this.isVisible()) {
  				this._triggerNode.classList.remove("dropdownTriggerOpen"); //$NON-NLS-0$
  				this._triggerNode.setAttribute("aria-expanded", "false"); //$NON-NLS-1$ //$NON-NLS-0$
  				if (this._selectionClass) {
  					this._triggerNode.classList.remove(this._selectionClass);
  				}
  				this._dropdownNode.classList.remove("dropdownMenuOpen"); //$NON-NLS-0$
  				lib.setFramesEnabled(true);
  				if (restoreFocus) {
  					lib.returnFocus(this._dropdownNode, this._triggerNode);
  				}
  				
  				this._isVisible = false;
  				if (this._selectedItem) {
  					this._selectedItem.classList.remove("dropdownMenuItemSelected"); //$NON-NLS-0$		
  					this._selectedItem = null;	
  				}
  				
  				if (this._boundAutoDismiss) {
  					lib.removeAutoDismiss(this._boundAutoDismiss);
  					this._boundAutoDismiss = null;
  				} 
  				updateScrollButtonVisibility.call(this, true);
  				actionTaken = true;
  			}
  			return actionTaken;
  		}
docs: Close the dropdown.