The PROJECTS suddenly dissapeared from my bookmarks. When I tried to add them back there they are not showing on the list. What happened?

Hi there, @Tom K.

Let me share some insights about the Bookmarks page in QuickBooks Online. 

The Bookmarks section is a part of the navigation menu in QuickBooks where you can add sub-menus. Since the Project page isn't a sub-menu but a part of the actual Menu, it won't be shown on the Bookmarks list.

If the Project menu wasn't showing in the Left panel, it's possible that it was hidden. To check, let's go to the Menu settings, ensure that the Project box is checked, and then click Save.

For further information about the latest QBO menu, please refer to this article: Understand the navigation menu in QuickBooks Online.

If you have any more questions about the Bookmarks page, please add them to the thread, and I'd be happy to answer them for you.