Test your display after dead or stuck pixels. A lot of new devices came with this kind of failing and you don't even notice. The application fills the screen, even the on screen navigation bar, with a single color at maximum brightness, allowing the user to easily find pixels that fail to show the certain color.
9 Available Colors:
Grey (50% of Red, 50% of Green, 50% of Blue)
White (100% of All colors)
Almost all type of screens work with those sub-pixel colors.
No ADS nor weird permissions.