Hello RayFox, go from Firefox button > Options > options > Security tab > CHECK "Warn me when sites try to install add-ons" [ v ], click OK to save it, exit firefox and restart it.

see for more info: Security settings

(by the way, your English is great !, better than mine for sure )

thank you

Hello ideato, thank you for your quick answer but that is not exactly I meant.

What I am speaking about is when you install programm on your computer, sometimes a plug-in is quietly installed. Like VCL player for ff or Skype plug-in or Raidcall one

when we said Add-ons, we mean extensions, themes, and plugins, it is all types of add-ons (if i understand clearly what you ask), see: Disable or remove Add-ons.

but if you install a program outside of firefox you can not take any notification from firefox, it is not possible, like downloading new version of Flash player, then install the version with closed firefox, you can not take any notification but when you open firefox you can see that Flash player is updated.

thanks

>but if you install a program outside of firefox you can not take any notification from firefox, it is not possible, like downloading new version of Flash player, then install the version with closed firefox, you can not take any notification but when you open firefox you can see that Flash player is updated.

That was exactly what I meant. Thank you very much. Now everything is clear for me.

you are welcome