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" when Firefox is closed because that prevails and prevents Firefox from opening tabs from the previous session.

If you use CCleaner then make sure that Session is unchecked in the settings for the Firefox application.

While this is a resolved thread the App Tab pinning SHOULD NOT be session controlled, they should be application saved and not be removed unless one actually removed them manually.

This needs to be fixed in a future update of Firefox 4

I agree.

gwmbox: I suggest filing a bug about this ;)

I had this with FF5, I changed Options-Privacy-Unchecked Clear History when Firefox closes. Now the App Tabs are always there.

morning,

i found that the icon you open to setup the tab apps has to be the same one everytime, i.e if you click on the firefox icon pinned to your taskbar to setup your tab apps, that is the icon you have to click all the time, (so clicking on anbohter firefox icon, the one on your desktop for instance will just bring up a fresh unedited firefox.

so what i done was pinned the firefox icon to my taskbar, then set up the tab apps, then drag the little firefox icon from the left of the address bar to your desktop. Now only my edited firefox will open when any of those 2 selected.

this worked for me

hope it helps

For anyone on Windows 7, I have a solution. I'm not familiar with other operating systems, so if someone could interpret this for others, I'd be grateful. Now, for anyone having problems with Firefox (any version, as far as I know) saving app tabs, check the things listed above, like Firefox saving history, ect. If those arent the problem (like if everything was working fine before, and you havent changed any settings), then do the following:

Make sure Firefox is closed. Now open the Task Manager (Ctrl+Alt+Del), and go to processes. If you see Firefox.exe (or anything with the description as Firefox), click on it and end that process. Then re-open Firefox and you should have your app tabs back.

This is also a fix for people having a problem with not being able to open Firefox (getting an error message that is something like "Firefox is already running. To use Firefox, close any Firefox applications that are running."