Sidebery for Firefox: Tree Tabs, Project Panels and Snapshot Restore Guide

The problem: tabs with no memory​

Anyone who has done a long research session knows the result. You end up with a long row of similar-looking tabs, and nothing shows which page led to which. Akinleye's complaint is that finding the page you need means scanning titles and guessing.

Vertical tabs, which Chrome and Brave both offer, help with space. His argument is that a long vertical list is still just a list.

What Sidebery does​

Sidebery is a highly configurable Firefox sidebar with several panel types. Its listed features include vertical tab panels in a tree or flat layout, bookmark and history panels, search, a customizable context menu and styles, and snapshots of saved windows, panels and tabs. It is free and open source. The Mozilla listing also says tabs can be shown as a simple flat list or as a tree, with an option to set a tree limit.

The tree is the part that matters here. Akinleye configures tabs opened from another tab to appear as children of that tab. Click a page, open something from it, then open something from that, and the whole chain nests under the page that started it. His example is a code repository. Its Issues page, the individual issues and the related documentation all sit beneath it, and he can collapse or expand any branch.

Panels and groups for separate projects​

He keeps separate panels for work research, GitHub projects, sports, social media and a few smaller uses. Each panel holds its own tabs, so switching projects doesn't mix them. Inside his GitHub panel he has named, colored groups for individual projects and general research, and the child tabs take on the group color.

A panel is a way to organize tabs. It is not a separate browser profile, and nothing in the reporting suggests it is a privacy boundary.

Other sources list related capabilities. They include groups (folders) with custom names, automatic per-domain/URL or manual tab coloring, sorting by title, URL or access time, and automatic unloading of tabs in a folded branch or inactive panel. Panels can also be bound to Firefox containers and use URL rules to move new tabs automatically.

The settings he changed​

He says he needed only a few settings:

• Automatic tree maintenance.
• New tabs opened from another tab placed as the last child.
• Auto-scroll, so new tabs are brought into view.
• A smaller font, so more tabs fit in the panel.
• Tab previews.
• Group sorting and inherited colors.
• Bookmarks and history shown inside the panel.

He gives these in prose, not as exact menu paths. Labels can change between versions, so check them against your installed copy. Context menus, keyboard shortcuts and styles can all be customized too.

Snapshots, and a restore caveat​

Sidebery can snapshot open windows, panels, groups and tabs. Akinleye set his to run automatically every three hours. That is his chosen interval, not a stated default.

He tested a restore of a research group: one parent tab with six child tabs, restored into a new window. The tree structure survived. Because he restored to a new window, the tabs opened in a different panel instead of returning to their original panel layout. He also says he can pick tabs from several groups and panels and restore just those into one new window.

That is one person's test, not a guarantee of how every restore behaves. If panel layout matters to you, try a restore with throwaway tabs before you rely on it.

One permission detail is worth knowing. One third-party listing of the add-on's permissions says unlimited client-side storage is used for the favicon cache and snapshots. It says the download-files and download-history permission is for auto-export of snapshots. Export is a separate step from taking snapshots in the first place.

Known limits and conflicts​

• Conflicts. Sidebery may conflict with add-ons that handle the position of new tabs, such as Tree Style Tabs, or add-ons that move or sort tabs. That can cause unexpected behavior or broken tab state at initialization. Run only one tab-positioning extension.
• Setup effort. Akinleye admits the initial manual setup can be stressful.
• The native tab bar. The add-on's listing reportedly says Firefox doesn't let extensions hide the native horizontal tab bar. Hiding it takes userChrome.css. One forum commenter shared a snippet that collapses it, but treat that as a community workaround and test it on your own build.
• Stability reports vary. One commenter on a 2024 forum thread said Sidebery was unstable for them and crashed their browser, and they switched to Tree Style Tab. That is a single anecdote, but it is a reminder to test on your own setup.

Chrome and Brave: how fair is the comparison?​

Chrome and Brave do have tab management. Google's Chrome Help documents tab groups and a vertical tab layout. Chrome's help page says that when browsing history and tabs are synced with a Google Account, changes to tab groups are saved and synced across devices. Brave's vertical-tabs announcement says pinned tabs and grouped tabs work as they did before. Groups can be created, labeled and color-coded.

So vertical tabs and grouping are not Firefox-only. Akinleye's actual claim is narrower: neither browser shows the opener-to-child trail between tabs. A third-party comparison, from a vendor of a competing sidebar tool, makes a similar point. It says Chrome's native vertical tabs fix the layout but not the tree. Chrome's own help page describes tab groups and vertical tabs but doesn't mention an opener-based tree, which is consistent with his claim. It doesn't prove the absence, and I haven't audited every current Chrome and Brave release.

Sidebery is also tied to Firefox. The same vendor says the extension doesn't exist for Chrome because Chrome's extension APIs don't allow this kind of persistent side panel. I haven't verified that claim independently, so treat it as that vendor's view.

Firefox's Nova redesign​

Akinleye says the Nova redesign makes Firefox's sidebar feel like a natural part of the browser, and that Sidebery fits into it. Mozilla's Add-ons blog says Firefox 157 shipped Nova on September 29, the biggest refresh of the interface since Proton in 2021. The browser frame is cleaner, the sidebar plays a bigger role, and vertical tabs are a first-class layout.

Nova is not a requirement for Sidebery. It is background for why his interface opinion changed. Not everyone is a fan. Commenters on Mozilla's post complain about the purple accent color, the rounded tabs and changed tab-group colors.

Mozilla's replies in those comments point to two ways out:

• Mozilla's featured Firefox Proton theme restores a more familiar look.
• Setting browser.nova.enabled to false in about:config and restarting Firefox turns Nova off. One commenter says Mozilla plans to remove that setting in a future version, so don't count on it long term.

Is it worth trying?​

Sidebery suits people whose research involves following links across many pages, picking the work back up later, and keeping several projects apart. If your tab habits are lighter, Chrome's or Brave's built-in groups and vertical tabs may be enough, and Tree Style Tab is the other tree-style option.

A reasonable approach:

1. Install Sidebery in a Firefox profile and make sure no other tab-positioning add-on is running.
2. Set new tabs opened from another tab to nest under their opener.
3. Set up a panel or two for your main projects.
4. Turn on automatic snapshots at an interval you pick.
5. Try a snapshot restore before you depend on it.

The verdict is that this is one user's workflow, not a controlled browser comparison. But the tree-of-tabs idea is real and documented. It is worth a look if your tab strip has turned into a haystack.