Hi Jon,
It is very simple. To make my explanation clearer, i will use ALL CAPS to indicate the components of the software.
The original usage of CONTEXT is to be used as "Contexts" (in GTD terms) like "@Phone, @Home, @work...etc.
Since user cannot use more than 1 flags in FLAG, u can workaround by using the CONTEXTS as FLAG also.
In this example, i will set my flags as days of the week, Monday, Tuesday, Wednesday...etc.
So, this is what you will see in your CONTEXTS list:
errand
Friday
home
John
Michael
Monday
phone
Ronald
Tesco
Thursday
Tuesday
Wednesday
work
The items on the list are arrange by alphabetical order. they are mixture of contexts and flags. To distingush them, i will add a prefix to each of them. so the end result is:
@errand
@home
@John
@Michael
@phone
@Ronald
@Tesco
@work
=Friday
=Monday
=Thursday
=Tuesday
=Wednesday
So now i know that those with the prefix of "@" are my contexts & those with the prefix of "=" are my flags & all of them live in the CONTEXT of MLO.
This way, you can assign more than 1 flags to any tasks.
Hope this is helpful. :-)