title: WPF Outside of window
body: <p>In Windows OS, when you run the installer file, OS asks permission to install the software. In that condition, window was focused and outside of window is inaccessible and <strong>blacked</strong>. And I searched to make such kind of window to create in WPF. But I just found inaccessibility opportunity. Is there any solution to customize the outside of the window color?</p>
  
  <p><img src="https://i.stack.imgur.com/kGynS.jpg" alt="such like this! I want to make the window sharper than outside of the window"></p>