NoFrills CPU - Asking for Root on Rooted phone

Hi,

All other apps that require root seem to request it - NoFrills CPU doesn't and consequently offers me no option other than to close the app. Just says "...Root access requires..." - without the usual dialogue affording me the chance to grant it.

Anyone else seen this?

Trying to get a little more life out of my Galaxy S6 by trying a few tweaks.

Thanks...