I thought I would share this with you just in case it is a bug.
This morning I prepared a new site using a Rockettheme template. The first extension I installed was jomsocial-pro_4.7.6. The installation went as expected but when I went to a module and tried to assign it to a certain page the result was definately not as expected.

I restarted the installation of the Rockettheme template from scratch and tried again. The result was the same after installing Jomsocial.
Once again I restarted the installation of the Rockettheme template but this time I installed jomsocial-445_4.4.5, an older version of Jomsocial. It worked fine with nothing like the attached image.
Now I updated to the new "pro" version and found the problem resolved.
I don't know if this is to do with the template or the version of Jomsocial.
This is only posted to advise you of the issue I experienced and no action is necessary on my site.
Best wishes,
Stay well.