Comment 8 for bug 1321903

Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:38.0) Gecko/20100101 Firefox/38.0

On the black penciled line (in the image I've attached above) is where the separation occurs for a `devPixelsPerPx` value of 1.2. I've only encountered this issue on `devPixelsPerPx` values that are between 1 and 2. It appears that this invisible line of separation changes it's x position on a linear scale based on the value of `devPixelsPerPx`