I have an app that shows up as an iframe on a Page. (Here's an example.)
Any idea what needs to happen on the Facebook side of the equation in order to have the tab at least make an attempt to load the app's page?
Thanks!
This is now a desired behavior, once you trying to visit Application Tab by being logged in as Page you'll be prompted to use Facebook as regular user:
To access this page, you'll need to switch from using Facebook as your page to using Facebook as yourself.
BTW, this was described in bug Blank app page which is marked as fixed (and the described behavior sadly was a way to fix this)...