App (pinned) 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/Profile_folder_-_Firefox Firefox
• http://kb.mozillazine.org/sessionstore.js
• 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" when Firefox is closed because that prevails and prevents Firefox from opening tabs from the previous session.

• https://support.mozilla.com/kb/Clear+Recent+History

Make sure that you do not run Firefox in permanent Private Browsing mode.

• https://support.mozilla.com/kb/Private+Browsing

@cor-el, I believe you are saying that app tabs in this version are not in fact permanent but are temporary, part of browsing history and subject to privacy options.

How disappointing!

In other words, app tabs are just like any other tabs and can be closed or over-written with other web page information and we have to be vigilant not to lose them.

Also, you're saying that the feature of app tabs is in direct contradiction with two privacy features (private browsing, and clearing history upon closing), which is something we weren't told when we were enticed by these features.

The only "handy" features of an app tab are 1) that it is skinnier in appearance and off to the left-hand side of the tab bar, and 2) Firefox can restart by reloading the app tabs to the state they were in when it was closed... but only if one disables certain privacy options.

We were led to believe that the app tabs we set up would be more permanent, not subject to browser history and privacy settings. Firefox's feature explanation is misleading:

"App Tabs

Take sites you always keep open—like Web mail—off your tab bar and give them a permanent home in your browser."

http://www.mozilla.com/en-US/firefox/features/

This is not true:

1) App tabs are not "permanent" but temporary (subject to our browsing behavior and settings). They do not help you "always keep open" your desired apps.

2) The app tabs actually do remain on the "tab bar." They do not reside "in your browser" but rather in your browser history.

SUGGESTED FIREFOX FIX:

1. Make these app tabs load like several home pages, regardless of the state Firefox was in when it was last closed. Or make them like bookmarks/favorites that are always in an open state. (This does not contradict the user's control over privacy. If the content of App tabs included private apps like Web mail, it's up to the user whether Firefox also remembers the username and password.)

2. When a person is in an app tab and browses away from the URL, either force the new address to open in a new tab, or bring them a pop up window that asks whether they want to change their app tab's address or not. This will ensure that their app is "always open" in an app tab.

I agree that this is a painful oversight.

My work-around at the moment is to use the protect tab feature in Tab Mix Plus .

Apart from the big yellow ! shield icon, it works ok.

But would like to see as an inbuilt feature of next FF

Thanks for the info on using the Protect Tab feature in "Tab Mix Plus". Seems to work well.