title: Is it possible to create a Custom FileDialog in SWT/RCP
body: <p>The existing FileDialog opens once we call the FileDialog constructor is -
  <img src="https://i.stack.imgur.com/sPx5c.png" alt="enter image description here"></p>
  
  <p>Now I want to customize the same.
  For example I want to add a new Button after Cancel named "Append".
  Can it be possible in plain java ?
  Also solution in Swing will work , then will use bridge to incorporate.</p>