PS:

Correction: The problem does NOT occur after a Firerfox-Restart, but after a Computer reboot.

What do you mean by "actual link"? ... This is no web-page, but a page locally created by an addon.

And I assumed that this is a firefox isuue, not an addon issue.

Menu -> Settings -> Generel page -> Startup Check - Open Previous Windows and Tabs

Check that you are not clearing Browsing and Download History when Firefox closes. See -

Restore previous session https://support.mozilla.org/en-US/kb/restore-previous-session#w_settings-may-be-incorrect

Of course, if changing those settings doesn't appeal to you, you can always Bookmark the page.

Thank you, RobertJ, ...

I checked all your points and all the points in the article too. ... But no succes.

And please let me emphasize, that all other tabs (normal and pinned), histories, entries, etc. ... get restored perfectly fine.

Only the addon-tab gets lost. ... And it only gets lost after a Computer-Reboot, NOT after a Firefox-Restart. ...

But meanwhile I found out, that it makes no difference, if it is pinned or just a normal (not-pinned) tab ... after a Computer-Reboot it is gone.

Pinned tabs are stored in sessionstore.jsonlz4 in the Firefox profile folder, so if you only lose pinned tabs after a reboot then this file might not survive a reboot.

Are you losing all pinned tabs or only this specific tab ? Do you only lose pinned tabs or do you lose other Firefox personal data as well ? Note that pinned tabs are connected to a specific window.

Use one of these to close Firefox if you are currently doing that by clicking the close X on the Firefox Title bar, especially if you have multiple windows open to prevent losing tabs in unnoticed windows.

• "3-bar" menu button -> Exit (Power button)
• Windows: File -> Exit
• Mac: Firefox -> Quit Firefox
• Linux: File -> Quit

Thank you cor-el,

Are you losing all pinned tabs or only this specific tab ?

Only this one single tab, which is a page created by an Addon, i.e. not a "normal" page. All other pinned (and not-pinned) tabs are restored just fine.

Do you only lose pinned tabs or do you lose other Firefox personal data as well ?

Nothing else is lost.

Note that pinned tabs are connected to a specific window.

I just use a single window.

And in the meantime I found out, that it makes no difference, if this specific tab is pinned or not-pinned ... in any case, after a Computer-Reboot it is gone. (Whereas after a Firefox-Restart it is restored just fine.)

Does this give you a hint?

Does this happen with the page form any extension or only from this specific extension /

Are you closing Firefox and give it enough time before you close down the computer or do you let the OS close down the computer with Firefox still running ?

Thank you Cor-el!

I tried the same thing with another tab of another extension: different behavior, it gets restored after reboot. This makes it look like the problem lies with the Addon itself.

I normally let the OS do the shutting down. Trying your advice with closing Firefox before rebooting, ... kind of solves the problem. The troublemaker-tab gets restored. This makes it look like the problem lies with the OS.

Is there a way to tell the OS (Linux Mint) to shutdown Firefox more gently? But I guess, that is a question for another forum.

Thank you very much for your help, Cor-el!