If memory serves, there is a limitation on the number of simultaneous Level II windows you can have open in IB and that's why I stuck with Alphatrade for Level II. I use 4 Alphatrade Level II windows and 2 small charts on one monitor and put my trading accounts, iHub, other charts, etc. in multiple windows on the other monitor. If I had a third monitor I'd probably open another 2 Level II's and some more charts but don't see going there anytime soon.
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