Appreciate the quick response... I tried the build.prop editing and this is where it got interesting... I cant edit it ... I've tweaked in the past with ES file explorer or root explorer but on this occasion the apps wont allow it ...does not allow the changes to be saved.... checked the root and thats fine, busybox is installed and working fine... my workaround was to tweak build.prop of the 3.97 rom of PA and apply it it from recovery.... this seems to have fixed the black screen in apps... so thanks for that.
I also just grabbed the 3.99 nightly of PA and build.prop already has the change applied, applying now.... result seems the brightness quirk is still there ... I tried the android sensor app and the lux settings seem to be correct so the light sensor is performing as expected the brightness is just not doing what its told... even if I set it to automatice brightness change the sensitivity and apply 100% to all different lux settings it just ignores it and dims the screen regardless... !!