qcenv.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documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.
Undo Command
Shortcut key: ALT+BACKSPACE
 
The Undo command retracts your most recent edit. It
restores the current line to its previous condition.
 
  The Undo command works only while the cursor is still
   on the edited line. Once you move the cursor off that
   line, Undo no longer has effect.