Returning Items in Norway - Consumer Rights?

Been having a debate with my Mrs and I'd like to get a second opinion!

In the UK you can return items within so many weeks, even if you've opened the box and taken the item out (some items not included like sanitary or digital items)

My Mrs says here in Norway you have to be able to wrap the item back up to almost it's original condition, so you shouldn't make a mess of opening items as the shops won't take them back. Is this true? What's the limit on taking things back?

As an example, we bought some curtains that turned out to be too long, she was panicking because she'd torn the plastic outer cover too much and didn't think the shop would take it back. This wouldn't have been a problem in the UK, is it here?