title: Drawing black rectangle on top of all controls in a c# winform
body: <p>I am currently working on a TileEditor software for game making.
  Almost everything is going smoothly. Here's the problem.</p>
  
  <p>I tried so hard to achieve this without any succes.
  Let's begin with a screenshot of the WinForm.</p>
  
  <p><img src="https://i.stack.imgur.com/lGLTP.jpg" alt="Screenshot of the application without the black square">
  You probably already figured the way the app works. </p>
  
  <p>So, I'd like to draw a semi-transparent black rectangle over the entire form except the Tile Selection Panel (the righthandside panel). I already have the function to find the correct points and location of the rectangle so that it does not appear over the right panel.</p>
  
  <p>Although when I try to draw it, it is drawn underneath the controls. Is there a way to draw the rectangle on top of everything in the form like this? </p>
  
  <p>(Photoshoped)
  <img src="https://i.stack.imgur.com/VEagt.jpg" alt="Black rectangle over form">
  Thank you so much for your time, it is truly appreciated. 
  Sorry for poor english, it is not my first language.</p>