In the Book The Hiding Place what happened at Nollie's house that so shocked old Katrien?

Old Katrien was shocked when she saw Nollie's new curtains, which were made from the same fabric as Corrie's dress that she had worn on the day of her release from prison. Old Katrien knew that the dress had been burned and considered it a symbol of shame and disgrace, so seeing it used for home décor was a surprise to her.