It seems that the order of the files within a Group, and the order of the Groups within a Target matters to uVision: the build process always examines the files in order as they appear within the Group, and the Groups in order as they appear within the Target. So, If I need to add file(s) and/or Group(s), how do I get them into the right order? Similarly, how can I re-order files and/or Groups if this becomes necessary? I'm using uVision v2.23.
This highlights another problem with uVision's Project management: there is no way to control when a Project is saved; if you make a mistake, there's no way to discard the changes (apart from the hacking about with renaming the backup files). I think this needs to be high on the list of enhancements for the next release!