Duplicate badges rework

This is a bit dirty (it retrieves the state from an unexpected location), but it's a slightly better solution than what was proposed before: re-render of the duplicates badge will still happen (mainly b/o the location changing as we click around in the app), but it will be almost costless. I'm afraid this can participate to a sum of very small slow-downs which would lead to a general slowdown of the application; we'll need to measure if we feel the app is too slow.