oWin:Register( <nClsStyle> ) -> <nil>

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 PARAMETER:

  <nClsStyle>  This parameter describes the style of the new window class,
               which in turn determines the behavior of the window. 
               For a list of applicable style flags please press:

                Related Topics:  and select  Window styles 


 DESCRIPTION:

  This method registers the TWINDOW class so that Windows knows next
  time what kind of windows we want to create.
  A Windows API-class can only be registered once, so this method sets the
  ::lRegistered class var to signal that registration has already
  been done.