I recommend the Multi-Account Containers extension by Mozilla, which has a "sort tabs" button that accomplishes what you want. https://addons.mozilla.org/en-US

I recommend the Multi-Account Containers extension by Mozilla, which has a "sort tabs" button that accomplishes what you want. https://addons.mozilla.org/en-US/firefox/addon/multi-account-containers https://addons.mozilla.org/en-US/firefox/addon/multi-account... I am not sure why this functionality is a separate extension - this is a bit confusing - but it's working for me.