Dear Mozilla when we can see (again) possibility to add two sidebars and tree style tabs?
I ask you Mozilla one more time. When you restore possibility to add two sidebars?
There is an extension for Tree Style Tabs in the one sidebar:
Firefox never had two sidebars. Legacy extensions had free run to modify the structure of the browser; obviously WebExtensions cannot make that kind of change. This bug to modify how the sidebar works has priority P5, which is too low to imagine changes any time soon, but there might be work ongoing on other bugs: https://bugzilla.mozilla.org/show_bug.cgi?id=1328776
I know that, but why Mozilla copy uncomfortable Chrome? Many years we can use bookmarks and side tabs side by side. Was It bad for us? NO!. About year ago we can test side tabs in Test pilot. Where is it? What was it for? Why Mozilla insists on horizontal tabs if monitors are much wider than years ago?
Where are functionality and ergonomics?
If you want to get that bug solved, recruit a developer to contribute the code. There must be someone out there who can do it.