Code

	  private void cmbShowID_SelectedIndexChanged(object sender, EventArgs e)
	  {
		RectangleF rr;
		foreach (Box bb in flowChart1.Boxes)
		{
		    //Get origin Rect(location & size)
		    rr = bb.BoundingRect;

		    if (cmbShowID.SelectedIndex == 0)
		    {
			  bb.FillColor = Color.Yellow;
			  bb.FrameColor = Color.Blue;
			  bb.Text = bb.Tag.ToString();
			  // resize to fit with text size
			  bb.FitSizeToText(FitSize.KeepRatio);
		    }
		    else
		    {
			  bb.FillColor = Color.White;
			  bb.FrameColor = Color.Black;
			  bb.Text = null;

			  // recover origin rect *********
			  bb.SetRect(rr, false);
		    }
		}
	  }