Skype's "Click to Call" add-on is a good (bad?) example of the harm caused by "side-loaded" add-ons. It causes Firefox to crash, hang, or take multiple seconds

Skype's "Click to Call" add-on is a good (bad?) example of the harm caused by "side-loaded" add-ons. It causes Firefox to crash, hang, or take multiple seconds to respond to mouse clicks. The add-on is quietly injected into Firefox by Skype's application installer and can't be disabled or uninstalled from Firefox's Add-on Manager. Users must uninstall it from the Windows' "Add/Remove Programs" Control Panel. https://bugzilla.mozilla.org/show_bug.cgi?id=1215970 https://bugzilla.mozilla.org/show_bug.cgi?id=1215970