FUNCTION MFIELDS()

  Short:
  ------
  MFIELDS() Pops up a selection box for current dbf fields

  Returns:
  --------
  <cFieldName> => field name or "" if none selected

  Syntax:
  -------
  Mfields([cTitle],[nTop,nLeft,nBottom,nRight])

  Description:
  ------------
  Popus up a box and presents an selection menu for the
  current dbf fields.

  [cTitle] is a title for the box.

  [nTop...nRight]  are coordinates of the box. Default
  is centered.

  Examples:
  ---------
   cFieldname := MFIELDS()

   // *or

   cFieldname := MFIELDS("Pick a Field")

   //*or

   cFieldname := MFIELDS('Pick a Field',10,10,20,40)

  Source:
  -------
  S_MFLD.PRG