Tips for using this buggy addon:
0. Deal with it.
Ok, 1. Organize with folders or folder trees instead of tab trees when you're working with a big chunk of tabs for maximum safety. Never ever should you make blank tabs (about:blank, new tabs, or blank pages) father of other tabs. Definitely gonna f up your tree after a restart if you spot buggy behaviors with tabs before it. This one is on Firefox.
2. You may often encounter scrambled up tree structures and missing tabs that are actually hidden after a restart, so you might want to have "expand all trees" in your context menu to make them reappear, or enable expanding trees with double click. This alternative doesn't always work though.
3. Use a session restore addon that saves and restores tab metadata 'by nature', just in case everything is beyond redemption. You might already be using one anyway so this tip goes the last.

I only updated past 57 because this add-on got ported. Absolutely essential for anyone using more then a dozen of tabs and integral to my workflow.

So amazing!

It is so wonderful that I can't imagine any more words to praise it.

But there are some issues that need to be addressed.

1. Can I disable the identity TAB while using it?

2. Can the color scheme of toolbar ICONS be more similar and more user-friendly than the ICONS in firefox?

3. In the "Tree Style Tab" sidebar, can I get a clean right-click menu that only contains close, mute, lock, and the menu items I checked in the Settings, and optional or does not include submenus created by other extensions?

待ちに待ったツリー型タブのquantum版です。
非常に良好に使用していますが、自動開閉があると嬉しいです。

Just found this today, not sure what rock I've been living under that made me not find this yet. The ability to customize with the userChrome.css file is almost endless and only limited by your imagination and your google-fu. Keep up the good work!

It is the best and the main reason I use firefox, but I have a problem, with new Themes for firefox, Tree background color changes based on which Theme I choose, is there any way I can keep original color or modify this color myself? with some Themes, color of tabs and their background becomes completely black or white !! so I can not even see tab's caption, thanks!