I agree with the previous comment Rated 1 out of 5 stars

Nothing more to add. This doesn't work

Rated 1 out of 5 stars

It just shows the tabs horizontally in a vertical sidewindow. Total crap

Rated 2 out of 5 stars

not work in ff 55

Only small icons Rated 1 out of 5 stars

Even after restart or the disable-enable dance the add-on shows small icons only

Works by disabling and re-enabling Rated 3 out of 5 stars

For me, it has never been working out of the box, but only by disabling the extension after firefox start and re-enabling again: This process transforms the tabs from compressed into a very small area on the left to working vertical tabs.

Doesn't work Rated 1 out of 5 stars

The tabs are shown horizontally and compressed into a very small area on the left. Totally unusable.

Doesn't work for me Rated 1 out of 5 stars

Only shows my 3 pinned tabs, at full title-long width instead of minimized.

Broken on 45 Rated 1 out of 5 stars

Tabs show on a left window, but they are horizontal (and thus I only see 3 at a time) instead of vertical.

Not work Rated 1 out of 5 stars

Just not work. Firefox 44.0.2

Works in Pale Moon Rated 4 out of 5 stars

This addon works in Pale Moon, great. However:
1) pinned tabs are not displayed properly. Please make pinned tabs smaller as their normal counterparts.
2) dragging a tab out of the current window to a new window causes the tab title to become "New tab"

does not work Rated 1 out of 5 stars

This addon opens a sidebar as you would expect but all the tabs load horizontally across the narrow sidebar so it looks awful and its totally unusable

Doesn't work in Firefox 41 Rated 1 out of 5 stars

Doesn't work in Firefox 41. Tried on clean profile without any other addons as well.

Doesn't work Rated 1 out of 5 stars

At all.

No good on FF 39 Rated 1 out of 5 stars

Totally busted.

Badly busted in v36 Rated 1 out of 5 stars

Unusable

Developer no longer involved Rated 3 out of 5 stars

I was told in an email:
"Sorry, I don't have any time to work on Vertical Tabs. It's on GitHub (https://github.com/philikon/VerticalTabs), feel free to fork it, or work with some of the other folks who have forked it and are improving it. I'm really not involved anymore at this point."

I have no idea how to use GitHub!

This user has a previous review of this add-on.

Buggy with FF32+ Rated 1 out of 5 stars

Moved to Tree Style Tabs extension, which works correctly with almost same functionality. Chrome also has vertical tabs in dev version

Rated 5 out of 5 stars

Best vertical tab add-on out there. Simple and lightweight, the only issue is the recent Firefox upgrade that broke vertical tabs on start-up. The work-around, to disable and enable the add-on, works.

Has anyone reached out to the author yet on this?

Does not work correctly in the FF 32.02 Rated 4 out of 5 stars

If after running FF32.02 make disabling/re-enabling this add only then it works. Need to fix it. Please.

Sill works on FF32, but not properly. Rated 3 out of 5 stars

The whole disabling/re-enabling thing works for version 32, but still has problems for me. Moving them doesn't work and sometimes tabs cannot be closed. This still needs a fix.