Hi coolreflection, did the extension buttons end up on the overflow menu at the right end of the bar?

If not, does it help if you disable and re-enable each extension on the Add-ons page? Hopefully they will re-initialize and Firefox will restore the original button position.

If not, you could check for the buttons among the unused icons in the box on the Customize page: Customize Firefox controls, buttons and toolbars.

If they are nowhere to be found, I suggest trying the "Restore Defaults" button at the bottom of the Customize tab to clear the current toolbar customization and then disable/enable each extension.

Any improvement?

On second read, if the extensions are not visible on the Add-ons page, Extensions panel, hmm, that shouldn't happen. You could try regenerating the extensions registry file:

Open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" Help > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the first table on the page, on the Profile Folder row, click the "Open Folder" button. This should launch a new window listing various files and folders in File Explorer.

Leaving that window open, switch back to Firefox and Exit, either:

• "3-bar" menu button > Exit
• (menu bar) File > Exit

Pause while Firefox finishes its cleanup, then right-click > Rename extensions.json to something like extensionsOLD.json.

Start Firefox back up again, and it should rediscover your extensions and rebuild the file. For externally installed extensions, this may involve permission pages.

Any improvement?

You can also try to delete compatibility.ini to invalidate the caches and re-initialize the profile.

You can click Restore Defaults in the Customize palette or possibly check browser.uiCustomization.state on the about:config page if the toolbar button to not return.