If you load a page and then switch to a different tab the content that should have animated does not and upon switching back the content that should be rendering at that time begins to render. If the sequence has already completed, no content appears. This appears to happen on both Firefox and Chrome on Windows and OSX. I'm not sure if it's a bug with runloop or jquery, so apologies if it's not related here. If nothing else it's good to know.
Windows 7 x64