No content is displayed when viewing facebook app in a facebook page's tab

I can view my application via the http://apps.facebook.com/app/ link and the content shows up correctly. I also added the application as a tab to a facebook page. However, when viewing the tab no content is displayed.

I am using version 3 of the facebook toolkit for a开发者_如何学Gosp.net.

From what I've read this is caused by a redirect being caused to login. I used:

protected void Page_PreInit(object sender, EventArgs e) { base.RequireLogin = false; But that doesn't fix the issue.

For debugging, I added a line to write to log file in the Page_Load and Page_PreInit. When viewing the app at http://apps.facebook.com/app/thepage.aspx a test string is written to the log at both Page_Load and Page_PreInit.

But when loading that same page - as a tab in a facebook page nothing is written to the log file; as if Page_Load and Page_PreInit isn't being hit.

Does anyone know what is going on?

Turns out facebook wants a / at the end of the canvas URL. Otherwise the relative links wont't work.