title: Why does my WPF GroupBox looks so weird?
body: <p>I have no style set anywhere in my application!
  <img src="https://i.stack.imgur.com/2wwFW.png" alt="alt text"></p>
  
  <p>UPDATE:
  <img src="https://i.stack.imgur.com/XfqXM.png" alt="alt text"></p>