Deleting more than one member at a time

I'm told that I should be able to delete multiple members at a time in my administrator section. It makes sense because it lets you select many at a time.  But it doesn't work.  I did a screen cap that you can view here...

https://www.screencast.com/t/bGFGyKlh

You have some customization on your site that is preventing delete functionality from working. The functionality works well on a default Dolphin site.