Desktop and Metro both limit the pagshow event to top-level windows/documents. We used to when we created the session store code Metro now uses. We lost it in the port. I noticed this because SessionStore.onTabLoad was showing up in cnn.com pageload profiles.

Comment on attachment 8350615 [details] [diff] [review] Top-level pageshow only v0.1 [Approval Request Comment] Bug caused by (feature/regressing bug #): Reduces the amount of times session is saved during a pageload. It should only happen once, but without this patch it can happen for iframes too. User impact if declined: Just a possible performance issue. Testing completed (on m-c, etc.): It's been on m-c for a while Risk to taking this patch (and alternatives if risky): Low risk String or IDL/UUID changes made by this patch: None

https://hg.mozilla.org/releases/mozilla-aurora/rev/a990d28d924e https://hg.mozilla.org/releases/mozilla-beta/rev/a4ceb800b3dc