Website compatibility: OSM editor Potlatch 2 does not work on Opera Dev 21.0.1419.0
Regardless of click to play or always load plugins the OSM editor Potlatch 2 will not run. For a brief moment you will see the inface after the loading screen finished then everything turns white.
https://www.openstreetmap.org/ after a login you can use the edit button.
edit: works on Chrome 33 just fine.