title: Rounded Form with System Shadow
body: <p>I tried to do with <code>SetWindowRgn</code>, and I couldn't.</p>
  
  <p>Can do that (the top 2 corners are rounded, the window has a shadow) like on this picture? </p>
  
  <p><img src="https://i.stack.imgur.com/dktgv.png" alt="enter image description here"></p>