Hi JD,
I can't remember if the "color by" option was removed for Deducer
0.6-3, but it will be removed for version 0.7-0 due out on the third.
The templates are designed to be the simplest possible interface to
get standard plots. To create more colorful/rich plots, the grammar of
graphics is the way to go.
try building you histogram like you usually do, and the right click on
"histogram" in the component list on the right. Select "Break out." If
you now double click it, it will show you all of the histogram options
under the hood. drag a variable into "colour" and you will have your
stacked histogram.
ian