I am having trouble with history.back() in an Ember app running in an iFrame after a transition made using Route#replaceWith, but only in FF. I have posted this issue here: Odd behavior with "history.back" in Ember app using "replaceWith" running in iframe in FF · Issue #11318 · emberjs/ember.js · GitHub. Any thoughts would be appreciated.
Update: this is not an Ember bug, but rather a Firefox bug. See 301307 - location.replace behaves badly, making accessible Ajax applications impossible.