unmaintained (Last updated May 14, 2018)

Thank you for creating a new Tree Style Tabs for newer versions of Firefox. However I have had to remove the add-on due to the colored tabs distracting and are leave text unreadable causing difficulty locating what tabs I am looking for. Can also be troublesome if looking for a tab buy color hue shade if colorblind.

I hope that some day there will be a toggle option to return to grey scale tabs fro those who need it.

Best wishes in your continued clever endeavors.

Works like expected.
Now has even the tweaking of the colors (like hue and saturation of used colors).

Style:
#sidebar-box[sidebarcommand="treestyletab_piro_sakura_ne_jp-sidebar-action"] #sidebar-header {
display: none;
}
does not work for your addon.

In "original" Tree Style Tab - works.

P.S.
only this css works:

#sidebar-header {
display: none;
}

Seems this fork stops updating, Tree Style Tab have many new releases, but this fork still use very old version with bugs and performance issues. So I re-implement colored tabs function using TST API (instead of fork) in separate light extension https://addons.mozilla.org/firefox/addon/tst-colored-tabs/

That's what I'm looking for.

Good!
But can we have color by group tabs like in Tab Kit? Instead of random color for each individual tab?
Thanks! :)