code: protected void applyFilter (SiteNode node) {
      	if (filter != null) {
      		boolean filtered = this.setFilter(filter, node);
      		SiteNode parent = node.getParent();
      		if (parent != null && ! filtered && parent.isFiltered()) {
      			// This node is no longer filtered but its parent is, unfilter the parent so it becomes visible
      			this.clearParentFilter(parent);
      		}
      	} else {
      		node.setFiltered(false);
      	}
  	}
docs: Applies the current filter (if there is one) to the node.
  This should be called anytime a change is made to a node that could affect its visibility in the filtered tree
  @param node