Hide the Invite Friend Button in the Detail Section of an Event

Hi, 
I'm looking for a way to hide/disable the Invite Friend Button in the Details Section of an event. I ask for this as I currently see DDOS attacks trying to exploit the mail sending form in that way. 
An option could also be to have this Invite Friend Button only visible when the User is registered. 

Many thanks in forecast for your help. 

Kind regards, Frank

I finally have found the button on the Themes Configuration page. I'm sorry for bothering you.
All best, F.  

Thanks Frank for the update. Please continue using the extension. If you have questions or need help, please don't hesitate to ask us

Regards,

Tuan