title: painted form contents won't stay painted
body: <p>I've tried setting ResizeRedraw, but it was not causing paint events on resize, so I began invalidating inside myForm_Resize. Now when I resize, I see that my background is being repainted, but as soon as I stop resizing, my control is being repainted with its background color. What am I doing wrong?</p>
  
  <pre><code>private void pbox_Paint(object sender, PaintEventArgs e) {
      Rectangle boardRect = pbox.ClientRectangle;
      using (Graphics g = pbox.CreateGraphics()) {
          g.FillRectangle(Brushes.Orange, boardRect);
      }
  }
  
  private void myForm_Resize(object sender, EventArgs e) {
      this.Invalidate(true);
  }
  </code></pre>