for some reason, firefox decided to group several of the taskbar icons together, and put them under one menu. this behavior is not wanted, was never requested, and cannot be undone. when using "customize" option for toolbar, this icon is hidden. see screenshot. also, extension "classic theme restorer" is installed as instructed by firefox support team as the only workaround available to disable the new Australis interface. edit: this seems to come and go with every firefox restart. sometimes icons are grouped, and sometimes they are not (maybe according to window initial size).