title: Howto add a custom border to a FormBorderStyle=None - form?
body: <p>I have a form with the property FormBorderStyle set to 'None' and with a custom bar on top side for dragging and buttons. </p>
  
  <p>Now I'd like to give the form a border because it's a child form and the parent form has the same background color as the child, so it's hard to see the child form.
  And no, I can't/won't change the background color.</p>
  
  <p>Help</p>