please add feature to open the same webpage in all container at once

Excellente! Most people here are praising MAC for its features, and they're right.
There is one review below by squarrell who finds he has trouble with the extension, but there IS a solution.
I've found that looking for the particular MAC tab for a particular account is irritating. The popup as you hover across the tabs is slow, and you have to run across them until you find the one you want. Better is to use MACs with the Simple Tab Groups extension. STG names them in its vertical dropdown, easy to inspect, and MAC puts an annunciator in the address field. An unintended method, but it works.
All hail Extensions!

FurryFox ❤️❤️❤️

This is now one of my must-have add-ons!

I am so happy to find this extension and switched to firefox for it. it really helps me with aws accounts.

For years I have *LOVED* my containers. However, a few months ago my containers stopped loading properly. I try to open my gmail in the proper container when I open Firefox (it always opens last tabs) and I have to reopen gmail in my preferred container. If I do not look at that gmail container often enough I have to follow the pop-up to open my gmail in the right container. I tried going to their GitHub for advice and the people were unhelpful and rude. I don't even know how to properly use GitHub! I wanted desperately to fix this issue.

I need my multiple inboxes open all the time. I cannot keep opening them in new containers because their original ones mysteriously stopped working.

Perfect for keeping youtube accounts and stuff like that separated by tab.

Dev/Test/Prod - works great for me keeping them straight.