I couldn't tell for sure because I use f.lux:
http://stereopsis.com/flux/
It alters your screen color based on what your current sleep schedule/geographical location is so it doesn't interrupt your sleep patterns. It's a nifty little utility when you work odd hours like I do, but when it gets later in the night (when the utility kicks in), it gets harder to tell some colors from one another, purple and brown being an example.
I'm not sure why that offends you, I don't see what's wrong with a purple knife... I knew that colors get altered by f.lux so I asked for clarity.