I don’t know how Tree Style Tabs handles pinned tabs, or whether it can be customized to do precisely what you want, but it’s something to look into at least:
Meh. Pinned tabs should be limited and flat. If you need to organise them into a tree you are probably using the wrong tool for the wrong job. Consider a directory of bookmarks you can open at once in a window (see Open All Bookmarks context menu).
I don’t know how Tree Style Tabs handles pinned tabs, or whether it can be customized to do precisely what you want, but it’s something to look into at least:
https://addons.mozilla.org/en-US/firefox/addon/tree-style-tab/
This doesn’t seem to work how I want, but I will try to see if it can be used for non-pinned tabs for organization.
@aspensmonster @rando
Meh. Pinned tabs should be limited and flat. If you need to organise them into a tree you are probably using the wrong tool for the wrong job. Consider a directory of bookmarks you can open at once in a window (see Open All Bookmarks context menu).