title: How to customize open/save file dialogs?
body: <p>I have seen some programs use custom open/save file dialogs in that manner they add some extra buttons there.</p>
  
  <p>How can I do this?</p>
  
  <p>Note that I want to use the basic open/save dialogs, so I dont have to re-create them, thus remain the buttons in the OS language. I only want to add some extra buttons there.</p>