public void unlink() {
		synchronized (ui) {
			if (next != null)
				next.prev = prev;
			if (prev != null)
				prev.next = next;
			if (parent.child == this)
				parent.child = next;
			if (parent.lchild == this)
				parent.lchild = prev;
			next = null;
			prev = null;
		}
	}