public void doundo (TreeNode pos1)
	{
		if (pos1 != Pos) return;
		if (Pos.parentPos() == null)
		{
			undonode();
			Pos.removeall();
			Pos.node().removeactions();
			showinformation();
			copy();
			return;
		}
		TreeNode pos = Pos;
		goback();
		if (pos == Pos.firstchild())
			Pos.removeall();
		else Pos.remove(pos);
		goforward();
		showinformation();
		copy();
	}