You can clone with
HTTPS or Subversion.
How to reproduce:
1. create a cover with a collection tile;
2. select compose tab;
3. Add a collection to the tile.
4. Go back to your collection and remove the collection.
5. Go back to your cover and see the mess.
We need a way to prevent this. We just need to show a message when the cover doesnt find the added collection.
Fix issue #138