"While some people find tab groups a convenient way to organize and manage tabs, others of us don't.This can particularly be a problem for those of us who sometimes like to move tabs around, as Firefox will automatically assume that we want to create a tab group...
They should have a place in Settings (I figure "Brower Layout" might be a good place) where one can disable tab groups. This would be more obvious and thus easier than disabling tab groups in about:config would be...
Tab groups may be the most requested feature in Mozilla Central, but there are also a number of us who absolutely hate them. " https://mercurie.blogspot.com/2025/05/how-to-disable-tab-groups-on-firefox.html