Thanks for the Developer for this extension. Scrolling tabs is a must. But on version 1.2.0, FF (59.02) don't remember the scrolling after I close FF. When I open again FF, I have to come back to option page, click on and off -disable scrolling to change tabs- option. On version 1.1.9 no problem. I have to downgrade to this version. I use tree Style Tab version 2.4.18 .