The status/wall configuration tab shouldn't be showing at all. That feature was removed in the v5.1 release, but the tab still shows when using Joomla 3.x. The v5.1.2 release, due out this week, will disable that tab properly as it's supposed to be.
The post to wall feature was removed in v5.1 because it doesn't adhere to Facebook's Application Policies after they were changed late last year.
I hope that helps explain, and sorry for the confusion.
Thanks,
Alex