the color system is a little more complicated than that... say the last trade was 2. If a buy comes through at 3 then it will be green. Any trades that follow it at 3 will be green also. If a trade goes by at 2 then it will turn red and all orders after that at 2 will be red. It has to do with the last trade price and the change that occurs. Red means downtick and green means uptick and its really just about averaging up or down when it comes to red/green.
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