Alternative add-ons for Firefox 57+: https://addons.mozilla.org/firefox/addon/mute-tab-webextension/ https://addons.mozilla.org/firefox/addon/mutelinks/ https://addons.mozilla.org/firefox/addon/auto-mute/ https://addons.mozilla.org/firefox/addon/mute-all-inactive-tabs/ https://addons.mozilla.org/firefox/addon/mute-sites-by-default/ https://addons.mozilla.org/firefox/addon/mutetab/ https://addons.mozilla.org/firefox/addon/auto-mute-hent/ Current tab context menu items: 1) Mute Other Tabs 2) Mute All Tabs