display 2d histogram data

Add 2d data source to experiment histogram display.
So if I'm reading this right (this is a bit confusing), there are two booleans that we're trying to take into account.  I only see 3 if statements here and not too much inside each w.r.t. all of the cases.  Aren't we missing a case here?

I'm not entirely sure and don't know as much about this as you do, but not having an else makes me nervous.