despite i am aware that design decision long long time ago was made to support tabs, and firefox developers were so proud of their decision that proposals on tabs were refuted with the stubbornness of flat earth believers, on operating systems like apple with mission control, gnome app selector the tabs are poisonous and take a lot of space. to find the contents easier one make windows instead of tabs. then one tab in every window takes up a lot of space.
history in the menu bar on top is useless as 1cm below on the back button history is again. bookmarks menu is double with the star, tools is double entry. the entries in the sidebar: customize sidebar, history toggle, bookmarks could go in the top menu, then there is no sidebar necessary any more.
