FireFox test tweak - wait for DOM flicker to end
FireFox test tweak - wait for DOM flicker to end

mysociety/popit,openstate/popit,mysociety/popit,Sinar/popit,Sinar/popit,mysociety/popit,openstate/popit,mysociety/popit,openstate/popit,mysociety/popit,Sinar/popit,Sinar/popit,openstate/popit