我也有这个问题，修正为：
该应用程序正在将用户重定向到Facebook（auth对话框）的登录屏幕，同时用户已经登录。
所以我更改了代码重定向到成功页面，如果登录，或对话框框如果没有登录。

I'm building a Facebook app and I have noticed that when attempting to get the login status of the user using their Javascript API, I sometimes get the error:

"Refused to display document because display forbidden by X-Frame-Options."

I've been able to reproduce this every time I hit the "check login status" page of the app only while using Facebook as a page, rather than my user account. This is easy enough to avoid now that I know this causes the problem, but obviously my users may not know this.

Is there a way to determine whether or not the user is using Facebook as a Page or not? Since that seems to pretty much ruin my entire app.

I had this problem too, fixed it with: The app was redirecting the user to a login screen from Facebook (auth dialog box), while the user was already logged in. So I changed the code to redirect either to the success page if logged in, or to the dialog box if not logged in.