Hi, I would then suggest you disable the Extension https://addons.mozilla.org/firefox/addon/loadtabonselect/ as it has not been updated in 10 months so the could I would say is messing up Firefox. There is a Support link but no contact information listed on the above URL.

Mozilla only ok's Developers Extensions for use with Firefox and provides the Developer with a Website to distribute it from.

In the URL above is a Search Box you can look to find a alternative to this extension that is current.

Please let us know if this solved your issue or if need further assistance.

Unfortunately it seems that the problem is with firefox and not some add-on. The add-on my sessions, which has the option to "enable lazy loading tabs" does the exact same thing. All opened unloaded tabs have a meaningless prefix usually starting with 55dadbec-14fb.

Firefox shows only a prefix instead of the tab title, when you open tabs unloaded.

If tabs are loaded and you unload them, on the other hand, tab title remains intact.

Please try : SAFE MODE

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

In Firefox Safe mode these changes are effective:

• all extensions are disabled (about:addons)
• default theme is used (no persona)
• userChrome.css and userContent.css are ignored (chrome folder)
• default toolbar layout is used (file: localstore-safe.rdf)
• Javascript JIT compilers are disabled (prefs: javascript.options.*jit)
• hardware acceleration is disabled (Options > Advanced > General)
• plugins are not affected
• preferences are not affected

TEST''''is issue still there ?

If yes please : uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files , C:\Program Files(x86) & C:\ProgramData Then restart system. Then run Windows Disk Cleanup. (Note: This should be Pinned and run Weekly, If never done below expect 10's of gig's) Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. But you should make a back up before you do :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Reinstall with Current Release Firefox 61.0.1 with a Full Version Installer

• https://www.mozilla.org/firefox/all/

Please let us know if this solved your issue or if need further assistance.

This behavior cannot be reproduced in safe mode because to open a tab without loading it, is only possible through an add-on to my knowledge.

Some legacy version of firefox had an option "load tabs on demand", but this was years ago.

Furthermore, I just installed firefox quantum, and used it only with one profile. On the same computer I'm also using legacy 52.9 esr firefox without this problem.

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

I did start in safe mode and there is no way to open a tab without loading it, because you need an add-on to do that.

Please, does anyone understand what I'm talking about?

I also reinstalled firefox.