Infinite Player Keyboard blues (and whites and blacks)

[HTBoogie]

Could someone kindly explain the relationship of the keyboard to the instruments in Infinite Player?

I see the usual white and black keys on all instruments and then a transparent blue over some keys. There is also the Key Range setting in the Instrument Options dialog and an input key range (e.g. for bass) or mapped key (for drums) on the racked instrument. These do not seem to correspond to each other. It seems that for the non-drum instruments the blue indicates the actual range of sampled sounds that are playable. Hitting the blue keys produces sound - the not blue keys no sound. For the drums, (these are from the recent group buy) there are several blue keys none of which produce sound. I was going crazy thinking I had something installed incorrectly. Yet, I accidentally noticed the Mapped Key setting (e.g., A2 for a gm splash). This key plays the sample.

What is the difference? How are they set? And, how are they related?

Thanks.