I want the sort of tool that was a commonplace when programming decades ago, so that the changes are apparent, are temporary but can be selectively made permanent by the editor - or not as the case may be - and are faultlessly incorporated into the xml when made permanent.
p.s. oh yes, it must run on Windows.
If you don't want to hand-edit XML, there are plenty of XML editors, although the good ones cost more than $0. Dave Crocker has one he likes.
R's, John