App Tabs are stored in sessionstore.js as part of the session data, so make sure that session restore is enabled and is working properly.

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

Thanks for the reply, Cor-el.

That article about session restore doesn't show how to ensure it's enabled in FF 4.0 (only up to 3.5). Can you point to me where in settings I can find it.

FYI I poked around in about:config and it appeared enabled there to me, but maybe I missed something.

I've verified that session restore is on and working properly. App tabs are still missing. Help, please?

Are you using Delete browsing, search and download history on Firefox to clear any items if you exit?

Are tabs restored if you select this?

• Tools > Options > General > Startup: "When Firefox Starts": "Show my windows and tabs from last time"

The "Clear Recent History" on exit was the culprit. Thanks.

However, this seems like a broken feature to me. Shouldn't it be able to clear the recent history without removing the pinned apps?

It is a bit controversial. If you want to clear the history of visited websites and you keep (App) tabs then you do not clear all history, but you would partly clear the history and in Firefox Delete browsing, search and download history on Firefox is all or nothing, so all selected data gets cleared and you lose open tabs including App tabs.

Thanks so much for help--it would have taken me quite a bit of time to figure it out on my own

You're welcome

Ok, but what if I want to just put the tabs in homepage, separated by "|"?

How do I notify Firefox that I want those to be pinned on open?

Where are TOOLS in 4.0?

I found "Tools" -- when you hit "options" you can't let it continue via the arrow to the subgroups. It surprises me that so much is made of Pinned Apps when they keep disappearing. I want to keep my cache cleared so I don't want to unselect "Clear History". Pinned Apps aren't going to work for me at all.

Press the F10 key or use "Firefox > Customize" to make the Menu Bar and other toolbars visible and remove the check-mark on "Tabs on Top" to place the tab bar in the old position.
You see the orange (on Linux gray) Firefox button if the Menu Bar is hidden (View > Toolbars > Customize or right-click a toolbar).
If you need to access the hidden Menu bar then press F10 or hold down the Alt key to make the Menu Bar appear temporarily.

That path is not found on my Mac. I want to turn "Clear recent history" off, but I can't even tell if it's on. I don't think it is.

If this upgrade is so great, why are there so many things wrong with it?

Pin as App Tab is dysfunctional if it is tied tied to the browsers history. Reason: If you set Firefox to remember browser history and then close Firefox with tabs open to different webpages the next time you open Firefox it will load all the tabs that were open at the end of your last session. Effectively the only thing Pin as App Tab does is make a smaller tab. What should happen is Pin as App Tab should allow you to clear browser history and the Pinned Tabs should be pinned and reloaded each time as a new session unless unpinned like Permanent Tab extension use to do. Right now Pin as App Tab should be called make Tab Smaller.

I agree PainterArt. I'm starting to look Chrome's way. FF 4.0 browser is still in deep Beta, in my opinion. This has wasted a lot more time than it has saved me.

Am I the only one that is losing toolbar customizations as well? In fact I have "Show my windows and tabs from last time" checked and it doesn't do it (all the time). The problem seems to be intermittent and yet happens often enough drive me crazy. Gotta be a bug, not a feature controversy when I lose the customizations, apptabs, AND the previously opened tabs. (No, I do not have "Clear history when Firefox closes" checked but even if I did I should not lose tool bar customizations.) Deleting sessionstore.js and sessionstore.bak fix the problem but only for a while and after redoing the customizations the problem comes back.

This problem is also affected by the Sync service, if you don't sync your history. Its not so bad not getting app tabs on the other PCs, the problem is that when you open Firefox on one of them it seems to overwrite the app tabs on sync. So when you go back to the original PC they are gone.

There's another even easier way to nuke all your app tabs:

1. Create some app tabs. quit and restart FF to make sure they come back
2. Right click on a link somewhere, and select "Open Link in New Window". Your new window appears. Note there are no app tabs in it.
3. Close the 'original' window which has the app tabs
4. Close the newly opened window without the app tabs

That's it. Your app tabs are toast. Reopen firefox, and "there they are, gone."

Also, it's way too easy to accidentally 'corrupt' a single app tab: Click on an app tab, and type a new URL into the Firefox address bar. Not only do you get taken to the new URL, but the app tab gets changed to it also.

The description in the post above is exactly what it happening to me and it is very frustrating.