On Preview Event

There is a logic error in the QR code that stops a custom preview from having an 'OnPreview' event. This can be corrected by replacing the procedure TQRPrinter.Preview in qrprntr.pas with the code below. -
procedure TQRPrinter.Preview; 
begin 
   if assigned(FOnPreviewEvent) then 
   try 
      FOnPreviewEvent(Self) 
   finally 
   end; 
   with GlobalPreviewInterface.Create(nil) do 
   try 
     PreviewControl := Show(Self) 
   finally 
     Free; 
   end; 
end;