Are you using the new to Firefox 47 Synced Tabs toolbar button? https://support.mozilla.org/en-US/kb/view-synced-tabs-other-devices#firefox:win7:fx47 Supposed to display in a "door-hanger" attached to the Synced Tabs button.

What extensions do you have installed? I would suspect one of them to have moved that display into the sidebar.

Also, can you still use Alt > History to see the "tabs from other devices"? I'm not currently using Sync, so I can't try that first hand. I can only use the KB support articles with that new feature.

See also the about:sync-tabs page. You can consider to bookmark this page.

You can open "about:" pages via the location/address bar

• "about:" is a protocol to access special pages

the-edmeister, Yes, I am using firefox 47 on both devices and am using the tab icon. I am not sure which extension I am using.

cor-el, That appears to be the window that I am looking for. However, now none of my devices will sync. When I try to sink on my computer it's hung up at "Fetching Synced Tabs..." and on my phone when I manually sync nothing happens. I disconnected and signed out of both devices then signed back in. No change.

Verify that your Synced Tabs display appears in the 'door-hanger' attached and below the Synced Tabs button, as shown in the support article that I cited.

mcjohns said

I am not sure which extension I am using.

Look in the Add-ons Manager Tab = { Ctrl + Shft + A }

or look in Help > Troubleshooting Information under Extensions.

You can check the about:sync-log page via the location/address bar to see if there are recent error logs available.

You can upload a recent log if the log is too big to put in a reply.

• http://pastebin.mozilla.org