Well, that's inconvenient. Could you take a look on the Customize panel and see whether the buttons are either in:

• the overflow list on the right
• the main box with available buttons

If you find them in either, you can drag them back to their proper spots. More info on Customize: Customize Firefox controls, buttons and toolbars.

If the buttons are nowhere to be found, you can try the "Restore Defaults" button at the bottom of the Customize panel. Then close and re-open the panel to see whether the buttons have become available.

Any improvement?

By the way, if you changed how Firefox handles history, or if Firefox has forgotten that you want extensions to run in private windows, you may need to update that on the Add-ons page. More info in this article: Extensions in Private Browsing.

The add-ins are NOT in the overflow nor the main box. They were there earlier today before I rebooted and the new version of firefox installed. Other then the re-boot, there were no changes made. The history shows all the previous items.

Any other ideas as to what changed and why??

I may have found the issue. I did not use the private browsing but found that a few of the add-ins got this set somehow (not sure if it was due to the update of firefox or something else). I removed this option from the few (was like 3 or 4) that had this and now all the add-ins appear to be back again.

Thanks for the lead as it allowed me to fix it.