title: How to associate a Windows application with a particular file type but share that association with other applications?
body: <p>If I create a new app, and associate with, say, the .xml file extension on a particular computer, when someone double clicks the .xml file, it will launch my app and pass the file as parameter.   But Windows seems to know what other files have the ability to work with that file type.  How is that set up?</p>
  
  <p>Also, when I save a Microsoft Word file as an .xml file, then later double-click on the file, it will launch Microsoft Word, even though the .xml file type is associated with something else, such as Internet Explorer.  Seems like there may be a stub associated with .xml file type which when invoked looks at the content and launches the appropriate app.</p>
  
  <p>Is there a Windows API, or some kind of a standard way to do that?</p>
  
  <p>What I wanted to create an app to do exactly what Word is doing -- i.e. save file in the .xml format, but when double-clicked, launches the my app instead of Internet Explorer.</p>