I know I can set Firefox to offline mode by pressing ''Alt'' on my keyboard and choosing "Work Offline" from the file menu. However, the browser doesn't actually seem to show me cached versions of sites after I do this. Instead, every site — even sites I visited literal moments before switching to Offline mode — shows me the same "'''Firefox is currently in offline mode and can’t browse the Web'''" message, and invites me to "Try Again" to go online. But I don't ''want'' to go online. I want to see the version of the site that, I hope, at least if Firefox behaves as I'd expect it to be have, is already saved in my computer's cache. How can I achieve this?