Hi Klaus,
Thanks for your information. I was thinking myself of the ForeGround layer, but I used it already for other purposes and erasing it just for the rectangle would be too much for my device, qua processing and rebuilding,.
I didn't know of the transparant colour and I do not really understand it, but , most important, it works quite well. Sometimes one or more lines of the rectangle remains, but that is not a serious problem.
Thanks again,
Regards,
Harry