Window size is not constant
When the screen resolution changes the size of the window changes accordingly. If the display resolution is a perfect 16:9 the resolution is 1000x600 or 1000x900 as expected, but with other resolutions the window changes to more unique sizes such as 1000x500 or 1000x700, making the browser fingerprintable. The window's height should always be standard 600 or 900.