ctrl+TAB -> next tab in firefox CTRL + SHIFT + TAB -> previous tab in firefox Switching between groups is easy. With a little practice, this becomes almost automatic. Click the Tab Group button at the far right side of the Tab Strip. For those of you who like keyboard shortcuts, you can use Ctrl + Shift + E. Click on a tab in the group you want to switch to and you'll exit the view and be returned to Firefox. The tab you clicked on will be active and only the tabs in that group will be visible. The keyboard shortcut, Ctrl + ` allows you to go to the next Tab Group and Ctrl + Shift + ` to the previous Tab Group. further info : https://support.mozilla.org/en-US/kb/tab-groups-organize-tabs

Thanks, but it doesn't answer my question,