I was wondering the same and resolved by closing all open tabs and starting over. Seems we'd done something to trigger shortcut bar showing up. I couldn't find out what I'd done, but read this in their documentation and figured it had something to do with what I had open:

Shortcut bars host shortcuts of views and editors and appear if at least one view or editor is minimized, otherwise, they are hidden.

https://dbeaver.com/docs/dbeaver/Application-Window-Overview/#shortcut-bar