Splendid add-on! Switched back to FF from Edge when found out about Sidetabs, been using it for half a year or so, and it just delivers on its promises. Thank you!
I only wish tab grouping also came with this thing, but it's good nevertheless.

Very good would be perfect if have option to group tabs

Lack of a narrow sidebar like Brave is the one thing that's been holding me back from coming back to Firefox.

Love it, thank you!

Absolutely love this extension. I also love the support for using it with userChrome.css as this has really made my vertical experience with Firefox much nicer.

With this extension and the sliding alternative in userChrome.css I really, finally, feel like the browser is out of the way of using it.

This is exactly what I have been looking for.
The userChrome.css instructions and generation is great. Thank you for your work on this. :)

I did have a slight issue getting slim bar and hiding the title bar and windows controls to work. I tried using other css I found online which caused other issues.
Then I removed it and used only your generated css and then it started working as expect so maybe it was a caching issue.

Looks and functions the closest to vertical tabs on Microsoft Edge in my opinion among the other add-ons I have tried so far like Sideberry, TreeStyleTabs. One thing I would like to see is an option to make the tabs' icons/title bigger so that it could be easier to click on.

This is exactly what I wanted for vertical tabs. Clean UI, matches my firefox theme, and it just works. I really like the copy-paste user chrome as well.

Really appreciate the inclusion of very straightforward and simple guide for CSS customization :) It finally looks clean enough for me to daily-drive vertical tabs

This is the extension that really feels like a native sidebar. It works great with themes. The design is simple but powerful.

Finally, a theme-friendly and Waterfox-friendly addon so I can tolerate looking at my vertical tabs (which I must have). More than tolerate, I can hardly believe the vertical tab sidebar has finally just become part of a fully themed interface, and I can enjoy the increased productivity without the constant irritation of my tabs looking different from the rest of the interface.

Does what it says it does.

Needs more features though, such as scrolling through tabs, and auto hide of sidebar.

Looks best if you use css to hide the original tab bar.