App tabs and Tab Groups (Panorama) are stored as part of the session data in the file sessionstore.js in the Firefox Profile Folder

• http://kb.mozillazine.org/Session_Restore

Make sure that you do not use Delete browsing, search and download history on Firefox to clear the "Browsing History"

Another issue that manually creates this problem:

Open browser with the App Tabs

Open a second browser window (no App Tabs here)

Close the first browser window using the top-right 'X' and then close the second browser window the same way (all browser windows are closed now)

Reopen the browser & the App Tabs are gone.

Although I rarely do this, sometimes I'll be working on multi-windows & forget the order of closing. I solved this my getting the "Toolbar Buttons" add-on [ https://addons.mozilla.org/en-US/firefox/addon/toolbar-buttons/ ] and putting the "Exit" icon in my navigation toolbar & had to train myself to use that to exit Firefox. Now I don't lose my App tabs.

MAC users on Snow Leopard - see my reply. This sort of is the same as above - ive logged it as a bug.

https://support.mozilla.com/en-US/questions/825628#answer-202340

Outside of losing my pinned tabs when opening a browser and then re-pinning my sites, I open a second browser and NO PINS are showing.

It appears ver. 5 has 2 major issues:

1. Losing pins when opening or restarting browser 2. No pins when a second browser (new window) is opened. Please help.

Me too. Same problem. The prescribed fix with the toolbar is nice. But I can't wait until the developers make it even better