Hey, Unfortunately this add on is not supported in Firefox 30 that came out this week. If you update this may no longer function. However to avoid duplicates you can use Firefox Sync. Every account synced to the attached account will show up in this place:

Duplicates are merged when the account syncs. Once the add on is updated to the new version it will be available again.

This is not an add on, it's a native feature in beta version, and yes, I'm using the newest Firefox Sync feature, and when the account syncs, duplicates are not merged and showing different devices while the fact is that all of them are the same device.

Hi Qattaj:

yeah rachel was a wee bit mistaken but hey i make mistakes all the time too :-) .

"Send Tab to Devices" is built into Firefox 29.0.1 and up.

Unfortunately other than filing a bug, there's not much you can do (you can't manually get delete the duplicate device OR get the server to delete the duplicate device) . Devices stay in the list that Send Tab to Devices uses for 3 weeks when the server deletes them!

Cheers!

...Roland

Also I filed a bug for this:

https://bugzilla.mozilla.org/show_bug.cgi?id=1024636

It's probably a duplicate of an existing bug but i couldn't find an existing bug!