title: "Busy" Effect Overlay
body: <p>I have a wpf application which does very heavy actions in which the user needs to wait while the application "thinks".</p>
  
  <p>What I want to do is, while the main thread of the application is thinking, another thread will disable the whole window and give it kind of a grayish color and a circular progress bar will appear in the middle of the screen.</p>
  
  <p>It's kind of a big question and I don't really need the whole code to do this just the general Idea.</p>
  
  <p>Thanks for all your help..</p>