Assegnate 5 su 5 stelle

Beautiful Add-on used for years, but lately icon not there any more [Status bar] - status bar is there - if I add another add-on it is shown on status bar on Firefox 56.0 64 bit !
I am puzzled.

Can it be fixed?
;p]

PS just added:
https://addons.mozilla.org/firefox/addon/classicthemerestorer/

Is back - thanks DocFlay - I did uninstall the above add-on - that is why it disappeared!