There is an extension that does roughly this: https://addons.mozilla.org/en-US/firefox/addon/total-suspender/ https://addons.mozilla.org/en-US/firefox/addon/tot

There is an extension that does roughly this: https://addons.mozilla.org/en-US/firefox/addon/total-suspender/ https://addons.mozilla.org/en-US/firefox/addon/total-suspend... (Not to say that it wouldn't be good if Firefox was better at it, but for those using Firefox, it might still be interesting until then.)