Suggestions for setting up four app-tabs + one home page:

Set up your home page (must not include those you pin Tools > Options > General

When Firefox starts: Show my home page

Home page: about:blank (or your own page)]

click on [|Ok|]

Reference:

https://support.mozilla.com/kb/How%20to%20set%20the%20home%20page

Pin the four tabs you want pinned, if not already done

When you close Firefox use File > Exit (not the X in the upper right corner which is for closing a window).

Bookmark the tabs you pin

I would suggest you bookmark the 4 tabs that are to be pinned then you can recall them as a group anytime. The fifth tab would be your home page according to my understanding. You may need to prefix digits to the name so sorting will not affect the order (or use bookmark separators).

time-saving tip

After loading pages to be app-tabs from a bookmark folder I use "Multiple Tab Handler" because I have it -- to select all of the tabs loaded with help of the Shift key to select from active tab to Shift+click tab, and then pin them all at once.

• http://dmcritchie.mvps.org/firefox/multiple_tab_handler.txt

Another usage tip:

I like to put a yellow marker tab as my last app-tab, then when I'm done with something I right-click on that tab and with the help of the "Multiple Tab Handler": extension I choose "Close right tabs". The page I use to mark that line is

http://dmcritchie.mvps.org/firefox/tab_capacity/toplevel/e.htm

While I have no trouble bringing up app-tabs from a previous session I like to close all of my tabs and recreate my app-tabs simply to clear out the cob-webs and tab history.

App-tabs are pretty much like regular tabs except that the tab is protected from opening a direct link or bookmark to another site within the app-tab -- that does not apply to bookmarks with substitution or javascript as they will open in the same app-tab.

App-tabs provide no more protection than normal tabs against web pages like this site while composing a reply where the typed text is frequently lost during composing and have to start over.

An article on how to use app-tabs

http://support.mozilla.com/kb/what-are-app-tabs

How to potentially create problems with app-tabs

https://support.mozilla.com/questions/840583

Thanks! Exiting through the File menu instead of the close button on the top-right solved the issue. Thanks for your time and extremely thorough answer.

Could you mark question as solved by clicking on "solved it" next to best answer. With app-tabs and saved sessions with multiple windows, it is seen now as having an immediate benefit in closing Firefox properly. Hope you've installed Multiple Tab Handler it is one of my favorite extensions, kind of a necessity for me for documentation as well.