title: How to create Visual Studio...file extension shells?
body: <p>I hope this doesn't sound like a stupid question, as I do not  exactly know what terms and technologies are involved.</p>
  
  <p>When you open a .cs file in Visual Studio, the code editor opens and displays the content in the main window (Code Editor) with syntax highlighting and stuff. When you open a .txt file, the same thing happens, except without any fancy extras because it's a plain text.</p>
  
  <p>But now, there are several files that open a whole custom UI that enables you to edit the base file .xxx with the help of dialogs etc. </p>
  
  <p>As an example, a ftp client: In the project, there's a file something.ftp with the following content:</p>
  
  <pre><code>connection = [
     server: 192.168.1.52
     port: 21
     startdir: "C:\dasdasd\asdasd"
  ]
  </code></pre>
  
  <p>So a UI pops up where you can edit the base file window based, connect to a remote server, view its remote directory contents etc.</p>
  
  <p>Are those so called <strong>Shell Extensions</strong>? Or <strong>Add-ins</strong>? Or <strong>Project Types</strong>?</p>