Preconditions:

All items in content tree in content structure are bookmarked.

Steps:

1. Log in to the back office
2. Go to Content/Content structure
3. Click [...]button next to the "Content tree" header
4. Click "Select all elements"
5. Click again [...]button next to the "Content tree" header
6. Click "Add to bookmarks" 

Actual result:

Alert is displayed that all items could not be bookmarked, but still only "Add to bookmarks" button is displayed.

Expected result:

If application knows that all items are bookmarked, there should be "Remove from bookmarks" button on the list.