Okay, allow me to say first off that I am working on developing my first FB app/page tab at the moment. I'm not looking for anything fancy yet, just workability.
That being said, I have managed to create a FB app that loads from the hosting requested, and displays it under the app page. I have also made it so that I can add it as a page tab to FB pages. What I am having an issue with is that clicking on the page tab for the app, it does not show any content in the iframe on the page, though it shows on the canvas page for the app.
So, my question is, do you have any ideas as to why it might be showing on a canvas iframe and not the page tab iframe? I am currently guessing that it has to do with how the signed request is processed, but am not completely sure. I am using the PHP SDK for FB given here: https://github.com/facebook/php-sdk/ for the FB-related functions, and am tracing through that currently for where I might be going wrong.
Any help is appreciated. Thanks. =)
I had the same problem and was able to solve it by providing different (http vs https) URLs for the secure and non-secure canvas and page tab URLs. Just remove post the non-secure URL for the non-secure canvas/page tab URL fields. I believe this is because Facebook doesn't check to see if the user has secure browsing turned on until after they have logged in.