fix walkthrough tooltip cosmetic issue
fix walkthrough tooltip cosmetic issue

fixes #1567

zbycz/iD,openstreetmap/iD,energiekollektiv/openmod.sh-id,digidem/iD,edpop/iD,openstreetmap/iD,andreic-telenav/iD,andreic-telenav/iD,kartta-labs/iD,mapmeld/iD,bagage/iD,ngageoint/hootenanny-ui,energiekollektiv/openmod.sh-id,AndreasHae/iD,tbicr/iD,edpop/iD,zbycz/iD,tbicr/iD,1ec5/iD,kepta/iD,mapmeld/iD,ngageoint/hootenanny-ui,openstreetmap/iD,kepta/iD,morray/iD,bagage/iD,kartta-labs/iD,edpop/iD,AndreasHae/iD,bagage/iD,mapmeld/iD,1ec5/iD,kartta-labs/iD,morray/iD,AndreasHae/iD,digidem/iD,ngageoint/hootenanny-ui,1ec5/iD