Galaxy S4 - problems editing contacts, linked to watsapp?

[Dinky Me]

My galaxy S4 has put my edit contacts function on lock down. It seems to be linked to watsapp only. Not idea how it's done this..? I've had to delete watsapp to rectify it. I can't seem to find in the settings how to resolve it. I've exported contacts to devise again. How do I stop it doing this if I get watsapp again?

Thanks guys.