We have fixed this issue, and have posted an update. Do let me know if you still have trouble getting Ref to work.
Was the update server side or should I wait for updated extensions for Firefox / Chrome?
Ah!.. We did test it with multiple inboxes, and was working. Can you please send us a screenshot to [email protected] so that we can look into this?
Sadly it doesn't seem to play nice with the "Multiple Inboxes" Gmail lab...
:-(