title: Is it possible to create QMainWindow with only outer border?
body: <p>I am trying to rebuild a screen record PyQt App, and the ScreenToGIF is a very good demo for me, it creates an interface which only has the border and record contents in the "Central Widgets", like this:</p>
  
  <p><img src="https://i.stack.imgur.com/fHVxr.png" alt="ScreenShot of ScreenToGif Software"></p>
  
  <p>with key functions of:</p>
  
  <ol>
  <li>The border exists and can be drag and resize by mouse</li>
  <li>the inner content is transparent</li>
  <li>the mouse click can penetrate through the app, and interact with other app beneath it.</li>
  </ol>
  
  <p>However, it is implemented in C# (link:<a href="https://github.com/NickeManarin/ScreenToGif" rel="nofollow noreferrer">https://github.com/NickeManarin/ScreenToGif</a>), I am wondering whether it possible to make a similar PyQt App without learning to be expertise about C#?</p>
  
  <blockquote>
    <p>Changing the background image of QMainWidgets to the desktop area been overlayed doesn't make sense, because mouse operation on desktop (such as double click to open files) should be recorded. Mouse event can penetrate the app (like Qt.WindowTransparentForInput applied for inner contents?)</p>
  </blockquote>