Works for me, as the other commenter stated. In addition I'm running the Tree Style Tabs addon, which moves all tabs to the left. While I look at a full screen

Works for me, as the other commenter stated. In addition I'm running the Tree Style Tabs addon, which moves all tabs to the left. While I look at a full screen Firefox I can move the mouse to the left side of the screen and the list of tabs will show up -> There's no way to get better screen estate usage, imo.