code: function(parent) {
  			parent = lib.node(parent);
  			if (!parent) { 
  				throw "no parent";  //$NON-NLS-0$
  			}
  			while (parent.hasChildNodes()) {
  				var node = parent.firstChild;
  				if (node.commandTooltip) {
  					node.commandTooltip.destroy();
  				}
  				if (node.emptyGroupTooltip) {
  					node.emptyGroupTooltip.destroy();
  				}
  				this.destroy(node);
  				parent.removeChild(node);
  			}
  		}
docs: Destroy all DOM nodes and any other resources used by rendered commands.
  This call does not remove the commands from the command registry.  Clients typically call this
  function to empty a command area when a client wants to render the commands again due to some
  change in state.
  @param {String|DOMElement} parent The id or DOM node that should be emptied.