Firefox 131 introduced native vertical tabs and tab groups. Combined with existing features like the sidebar, these change the browsing experience meaningfully. Here's a practical guide to the new UI.
Vertical Tabs (Firefox 131+)
Enable: Settings → Tabs → "Enable vertical tab sidebar"
Or right-click on the tab bar → "Move Tab Bar to Sidebar"
The vertical tab bar appears on the left (or right, configurable) as a sidebar panel. Shows:
- Tab favicon and title (not just favicon like the horizontal bar at scale)
- Current tab highlighted
- Drag to reorder tabs
Combining with hiding the horizontal bar:
The sidebar doesn't automatically hide the horizontal tab bar. To hide it:
- Right-click horizontal tab bar → uncheck "Show horizontal tab bar" (Firefox 133+ may have this option)
- Or via userChrome.css:
#TabsToolbar { display: none !important; }
Vertical tabs with Tree Style Tab extension: Native vertical tabs don't have parent-child hierarchy (nested tabs). If you need hierarchical organization, Tree Style Tab still provides that. You can use it alongside native vertical tabs, though typically you'd pick one.
Tab Groups (Firefox 131+)
Create a tab group: right-click a tab → "New Tab Group" → name and color the group.
Or drag one tab onto another — a group creation prompt appears.
Collapsing groups: Click the group label to toggle collapse/expand. Collapsed groups show as a small colored indicator.
Managing groups: Right-click the group label → rename, change color, or ungroup.
Tab groups persist across Firefox restarts (unlike regular tab sessions which can be lost in some crash scenarios).
Use cases:
- Group tabs by project: all "work-project-a" tabs together
- Group research tabs: collapse when not reading
- Group social/news tabs: keep separate from work
Tab groups complement Tab Manager & Session Saver: use tab groups within a session for organization, and Tab Manager sessions to save and restore different working contexts.
The Sidebar
Firefox has had a sidebar for years (bookmarks, history, synced tabs). It's been revamped:
Toggle: Click the sidebar toggle button in the toolbar (or View → Sidebar).
Sidebar contents:
- Bookmarks
- History
- Synced Tabs (from other devices via Firefox Sync)
- Vertical Tabs (new in 131)
- Extensions can add sidebar panels (Tree Style Tab, Firefox View)
Multiple sidebars: Firefox lets you switch between sidebar panels. Vertical tabs, bookmarks, and history can all live in the sidebar space.
Firefox View
Firefox View is a new tab-like interface accessible via the Firefox logo at the top of the tab bar:
- Recent Tabs: Tabs you've closed recently (like Ctrl+Shift+T but browseable)
- Open Tabs: All tabs across all windows in current session
- Synced Tabs: Tabs open on other devices (needs Firefox Sync)
This is useful for finding something you had open earlier without searching history.
The New Tab Page Customization
The default new tab page has:
- Top Sites: Most visited sites (tiles)
- Recent Activity: Recently visited pages
- Sponsored stories (can be disabled)
Customize:
Settings → Home → Firefox Home Content → toggle each section
For minimal new tab: disable stories, disable sponsored, keep just the search bar.
Or: Settings → Home → "Homepage and new windows" → change to "Custom URLs" → set your own URL or use about:blank.
Search From the Address Bar
The address bar is a unified search and navigation bar. Configure it:
Settings → Search → Default Search Engine
Keyword searches: Set up one-click searches.
Settings → Search → One-Click Search Engines → Enable any engine.
Then in the address bar, type the engine keyword + space to activate it:
-
@g search term— Google -
@w article name— Wikipedia - Any keyword you configure
Compact Toolbar
Firefox 89 removed the "compact" toolbar density. You can restore it:
Settings → Customize Toolbar → Density → "Compact"
If "Compact" isn't visible (some versions removed it):
about:config → browser.uidensity = 1 for compact
Tab Scrolling
With many tabs: Firefox scrolls the tab bar by default rather than shrinking tabs to unreadable sizes.
about:config → browser.tabs.tabClipWidth — minimum tab width before overflow scroll.
Or use the << and >> arrows at the ends of the tab bar to scroll.
See all tabs: Click the ⌄ dropdown at the right end of the tab bar to see a searchable list of all open tabs.
Pinned Tabs
Right-click a tab → "Pin Tab" — pins it to the left side, shows only favicon, can't be accidentally closed.
Useful for: always-open tools (calendar, communication apps, monitoring dashboards).
Pinned tabs persist across Firefox restarts.
Tab Multi-Select
Hold Ctrl while clicking tabs to select multiple. Then:
- Right-click → "Close Tabs" — closes all selected
- Right-click → "Bookmark Tabs" — saves all selected to a new folder
- Drag to reorder as a group
- Right-click → "Move to New Window" — detaches selected tabs into new window
Multi-select is useful for bulk tab management: select all the tabs from a finished project and close them at once.
Performance Impact of Features
Native vertical tabs: minimal performance impact (they're just CSS-repositioned existing tab UI).
Tab groups: minimal impact.
Sidebar: the sidebar panel loads its content lazily. Keeping it open to bookmarks doesn't significantly impact performance.
The most impactful change for performance is tab count — each tab uses memory regardless of UI organization.
The Full Modern Firefox Tab Workflow
With all features combined:
- Tab groups: Organize by context within a window
- Vertical tab bar: Better visibility of tab titles at scale
- Tab Manager sessions: Save/restore whole working contexts
- Firefox View: Find recently closed tabs
- Pinned tabs: Persistent tools that survive session changes
This layered approach handles everything from "I need to find that tab I had open" to "I need to save this whole working context for tomorrow."
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