qp.hlp (Topic list)
Important Notice
The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.
Duplicate Command
 
  Use the Duplicate command to create a duplicate of the
  active file window. A new window opens and displays a
  copy of the source file in the active window. You can
  view a different part of the source file in the
  duplicate window.