After a bookmark creation, it will be automatically shown in the favourites drop-down for the original creator, unless a maxium limit of viewable objects is reached.
Anyone else who wants to see them listed in the drop-down, needs to add them manually from the Repository
and by ticking the Show
Sometimes users who had bookmarks shared with them may see them disappear from the drop-down, and then have to search for them in the Repository and re-add them.
When the original creator of a bookmark removes it from their own favourite drop-down. This causes it to be unlisted for all users that had the bookmark shared with them.
For the time being, re-add the bookmarks from the Repository is the only viable solution. This has been logged as a Feature Request (ID 1564) and will be evaluated for future releases.