I bought some 'mitten clips' and stick on Velcro. Attaching the stiffer part of the Velcro around the side bars of the scroll frame, I attached the mitten clips to pieces of the other part of the Velcro (just remove a little of the backing so that only the part that is needed is sticky), and I have adjustable side clips to keep the fabric taut. For a narrower or wider piece of fabric, I can readjust the Velcro!
Recently I saw some Velcro electric cord holders which would be great for this - if I can find were to buy them!