XPgetScreen()
  Return area of a screen text as a Memo var.
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   Function:   XPgetScreen()

               XPgetScreen() retrieves text from a screen portion and returns
               it in a memo variable. Just like XPgetText() but with more
               lines.

   Syntax:     XPgetScreen([nTop,nLeft,nBottom,nRight]) --> cMemo

   Arguments:  The screen portion to retrive. when omitted it defaults
               to the whole screen.

   Returns:    The screen portion as a Memo.

   Usage:      /* Get whole screen */
               ScrMemo := XPgetScreen()