public void mouseEntered (MouseEvent e)
	// start showing coordinates
	{
		if ( !Active) return;
		if (DisplayNodeName)
		{
			GF.setLabel(LText);
			DisplayNodeName = false;
		}
		int x = e.getX(), y = e.getY();
		x -= O + OTU;
		y -= O + OTU;
		int i = x / D, j = y / D; // determine position
		if (i < 0 || j < 0 || i >= S || j >= S) return;
		if (GF.showTarget())
		{
			drawTarget(i, j);
			iTarget = i;
			jTarget = j;
		}
		GF.setLabelM(Field.coordinate(i, j, S));
	}