Norton Toolbar disappeared from Firefox 40, 40.0.2, and 40.0.3

I'm using Windows 7 with NIS 21.7.0.11  (that's the latest version Liveupdate gives me)

I was breezing along today using Firefox 40.0.2, when I looked up and noticed the Norton Toolbar had completely disappeared.  It was there earlier today.   I had previously had Toolbar version 2014.7.12.35, and until now it would show up normally in the Firefox Add-ons.  It's not that it is merely disabled.  It cannot be found by clicking in the top Firefox menu bar on View>Toolbars>Norton Toolbar; there is no entry there for Norton Toolbar.  Likewise, when I open the Firefox Add-ons page, there is no evidence of Norton Toolbar at all under extensions.   Norton Toolbar is still present in Internet Explorer.  Everything is enabled in the Norton control panel GUI settings.

So I uninstalled Firefox 40.0.2, and installed Firefox 40.0.  Still no trace of a Norton Toolbar.   So I uninstalled Firefox 40.0, and just installed Firefox 40.0.3.  Still no Norton Toolbar.  Any suggestions?    Do I need to do a clean install of NIS?

Thanks!

BTW, if a moderator sees this, I just noticed in the "Labels" section below, it says "Norton Tollbar" instead of "Toolbar."