Hello,
I think I have found a solution. (Or at least this worked for me, in that I was able to run a report and get a result.)
The first tab is "Choose Payee" I pressed Command+A on my Mac to "select all" (I assume Control+A will work for Windows users,) Now having selected all payees, I was than able to select the expense category (Under the "Choose Categories" tab,) that I wished to report on, and then proceed through "Choose Account" (select all on the menu to the right,) and press on OK to run the report.
Having done this once, all payees (and all accounts) are selected if I attempt to run the report again. This agree with the advise given at
http://wiki.mthbuilt.com/Customizing_reportsThe other way to say this is "Is there a menu missing from the "Choose Payee" tab?"
Hope this helps, as I have stuggled with this for some time and mthadm seem to be very quiet on assistance for this one.
Cheers,
Stretch