This is why I stick with Firefox.

Works as intended. This makes trolling 100% easier. No longer do I need 7 different browsers to accomplish my tasks.

a little suggestion:
if i place the toolbar button beside tabs (or the original new tab button), could it be aligned to the left?

I'm using it since many months now, and it made my life so easy. Don't have to open different browsers for multiple web based emails.

Works as designed.

New Features:
1. Bookmarks by containers - low priority
2. Save settings by containers - like when i apply charting settings on yahoo finance, and open another tab inside same container, those stock chart settings are gone and i have to reapply them.

So cool :)
This allows me to "box" all google websites in its own container and all Amazon websites in another.
Plus, I can have as many containers as I want, in case I want to log into something with different accounts at the same time.

The importance of a browser extension like this can not be overstated. The fact that Mozilla them self maintain it makes me feel warm inside. Much privacy very container!

Usability changes/default selected container type when opening the popup/shortcuts to open container

best add-on ever created

Very useful. I'm using multiple accounts on for the same site and with this extension I don't have to deal with multiple browsers and incognito mode.

This is one of the most amazing feature of Firefox, at work we use the GSuite and Chrome with multiple accounts: this add-on allows me to ditch Chrome entirely.
I am also converting other colleagues to it, little by little.
I am an IT Technician at Salesforce :)

Works best when you create 1 container per website (twitter, youtube, etc) and set it to automatically open in the appropriate container.