I'm on the latest FF 140.0.1 on Linux and I adore tab groups, I'm using it more and more to organize my browser windows. I am using the default (horizontal) tab group layout. Because I have a lot of tabs in the window, I collapse each existing tab group and sort tabs between tab groups. I can move a tab into an expanded tab group with drag and drop. But I tried dragging and dropping a tab onto a collapsed tab group, even holding it over the collapsed tab group to see if that would work. Nothing seems to register, is it possible? I would like to move a tab by drag and drop without expanding the collapsed tab group and move the window focus to the next tab. This would save time when I am organizing tabs! The alternative is to Add a tab to a collapsed tab group, which also expands it and consumes horizontal real estate, forcing me to scroll (further) to return where I was organizing tabs. So I collapse the newly expanded tab group, scroll back to the next tab I want to organize into a different tab group, and repeat but this causes a lot of scrolling navigation to my workflow. It makes complete sense and I really like using menu navigation to add tabs to a specific group because it is discreet and I wish I could move tabs with the same method. I searched Settings > Tabs and then about:config for browser.tabs.groups.* (and then every preference with tab in it) and couldn't find anything that made sense to me. Thank you for any help!