FB.getLoginStatus hanging only in HTTPS/SSL mode

I'm trying to enable HTTPS support in my app before the October deadline, but the JavaScript call FB.getLoginStatus never calls my callback.

I'm using OAu开发者_如何学Pythonth2.0, and I added the channelUrl parameter. This works fine in HTTP mode. FireFox is reporting no security warnings during page load, all files appear to be correctly served via HTTPS, and all references in the html/js code appear to be updated to point to https:// instead of http:// (including the channelUrl file).

What else can cause the getLoginStatus to not return?