Open Tab Right, Close Tab Left gives you predictable, intuitive tab behavior in Firefox.
Opening tabs: Every new tab opens immediately to the right of your current tab โ never at the far end of the tab bar. This works for Ctrl+T, Ctrl+click, middle-click, right-click โ Open in New Tab, target="_blank" links, bookmarks opened in new tabs, and duplicated tabs.
Closing tabs: When you close a tab, focus always moves to the tab immediately to its left. No more jumping back to a random "source" tab across the bar.
Tab group aware: If you're working inside a tab group, close behavior stays within your group โ focusing the left neighbor inside the group first, only leaving the group if it's empty. New tabs opened from within a group stay in that group, even from the last tab.
Two simple toggles in the popup let you enable or disable each feature independently.
