I think it would be nice to have folders you can give useful names.
These should act as a node of the tree only for organizational purposes - cannot be focused like a normal tab, but can be renamed of course.
I saw that I could set up a hotkey for "New Container Tab". I tried to set its hotkey to Ctrl + Shift + A. However, nothing happened when I pressed this key combination, even after restarting Firefox.
Try typing this on the URL bar: about:treestyletab-group?New%20Group
Firefox shows:
Hmm. That address doesn鈥檛 look right.
Please check that the URL is correct and try again.
(also tried to substitute %20 with space - same result)
Just so I am being clear ... enter in the URL bar:
Is that what you tried? This has worked for quite some time, but I assume you have latest updates? (No spaces in any of the URL)
That exact string also gives me the said error.
I have the latest updates I believe (Tree Style Tab & Firefox)
Hold on ... when I pasted it in the URL bar right after creating a new tab I got that error.
But when I pasted it in the URL bar where there was already about:addons it worked.
I tried again to define a shortcut. This time Ctrl+Shift+Z. The only thing that happens is I get this dropdown menu and if I click one of the options it opens a new tab (not a folder tab):

And this also only works in an about:addons tab or in an existing folder tab (as created by entering the URL you gave me)
That is interesting. Thanks for reporting back. I am wondering if it might be a Linux related item. @piroor will likely need to chime in on this one. (Have you tried this on Windows as a test point?)
about:treestyletab-group?New%20Group works for me in a freshly-opened about:blank tab and in a tab that was opened to a different issue on this tracker and I'm on Kubuntu Linux 14.04 LTS with current Firefox Developer Edition (62.0b19).
That said, if you want to create a shortcut for it, you might prefer the approach I use. The Multiple Tab Handler addon will integrate with TST so you can click-hold on a tab, then drag to select a range of them, then let go and choose Selected Tabs > Create New Group from the resulting context menu.
@ssokolow After installing that extension I don't see an option like that in the Selected Tabs submenu.
Turns out it is not enabled by default and must be turned on in the addon options. Now it works.
I also have the problem that the "about:" URL has stopped working. I'm on mac Firefox Developer Edition 62.0b19 (64 bit).
Because WebExtensions API doesn't provide any ability to define custom about: URIs, fundamentally WE-based addon cannot provide any shorthand URI for its own purpose. So TST just tracks the actually loaded URI of a tab and simply replaces about:treestyletab-group to an effective moz-extension: URL. However, when WE API don't notify loading of the about:treestyletab-group URI for a tab, TST cannot detect it. I guess that it is the originally reported case.
I close this because outdated.
BTW, now TST has a builtin context menu command "Create New Group from tabs" for tabs multiselected via Ctrl/Shift-click.