Apple Logic Pro /LogicExpress Discussion

I've forgotten way too much of what little I've ever learned about
MIDI and the Environment.

MIDI (both external and internal keyboard) triggers a Drum Kit
(evidently GarageBand) on every track, whether new empty project or
existing projects. In Arrange it happens no matter which track I make
active (audio or instrument), and no matter what instrument is
assigned in the Inspector, even if NO instrument is assigned.

I'm sure I can fix this in the Environment, so I started by checking
the Manual, starting from p. 868. About 10-12 pages into it I still
couldn't figure out what to look for. I went to the MIDI Instr layer.
Figured this might be helpful:

(I don't see how to attach images here, and HTML didn't work, so just
go directly:)
http://www.chuckbryant.com/logic.png

To my untrained mind it SEEMS related, so I deleted one component at a
time, and finally all of it, knowing I could quickly undo or close
without saving if any step caused other or more serious problems. No
change. 

I tried various things with Port and Channel but couldn't get
the magic. Couldn't find anything on any other layer that seemed
clearly related, but obviously I'm missing something.

Obviously I'm lost here, so if you're a generous soul willing to
explain what to do, please specify every step and speak vewy, vewy
slowly. I'll check back Saturday.

OS 10.4.11, Studio 8.0.1.

Thanks,
chuck