I have stumbled across a way to make the sidebar hide again. I have Firefox running full screen with 3 pinned tabs. If I move one of the pinned tabs, or even drag it enough to enable the move without actually dropping it, the sidebar will re-hide. It may require dragging the tab far enough left to overlap the sidebar, which triggers the hide.
I have stumbled across a way to make the sidebar hide again. I have Firefox running full screen with 3 pinned tabs. If I move one of the pinned tabs, or even drag it enough to enable the move without actually dropping it, the sidebar will re-hide. It may require dragging the tab far enough left to overlap the sidebar, which triggers the hide.