[Q] Low Brightness Problem!!! topic

HI
i turned off auto brightness and screen tone and adapt display to standard so i changed brightness to max but after some seconds its screen keep dimming. i used RootDim app and maxed my brightness to 255 but after some sec it changed to 219 even the status bar brightness was max...
it happens in whole of my phone not in specefic app
i use android 5.0.1 India official