title: Blurring the background of a semi-transparent form (like Aero glass)
body: <p>I have a borderless, non-resizable WPF form (WindowStyle=None, AllowsTransparency=True, ResizeMode=NoResize) with a semi-transparent background. Here's a picture of how the form, a semi-transparent red rectangle, looks right now, running on top of Notepad:</p>
  
  <p><img src="https://i.stack.imgur.com/Aeen1.png" alt="the form as it currently appears on top of Notepad"></p>
  
  <p>However, I'd like the background to be blurred, like how Aero glass does it, except without all the fancy window borders and colored background with stripes - I'd like to handle that myself. Here's a mockup of how I want it to look like:</p>
  
  <p><img src="https://i.stack.imgur.com/KLE5s.png" alt="the form as I want it to be - blur anything that&#39;s below it"></p>
  
  <p>How can I achieve this in the most efficient way possible?</p>
  
  <p>WinForms or WPF is fine by me. Hopefully it should use the same thing Aero glass uses (I'm fine with it working only with Aero enabled), instead of something crazy like capturing the screen region below as a bitmap and blurring that.</p>
  
  <p>Here is a picture of what I DON'T want:</p>
  
  <p><img src="https://i.stack.imgur.com/WZcr8.png" alt="I don&#39;t want the entire Aero glass window chrome"></p>
  
  <p>I know this is possible and I know how to do it, but I DON'T want the entire Aero glass window chrome, or the borders and title bar, or the window to have the user-set Aero glass color, JUST the effect of blurring whatever is below the window/form.</p>