I installed an add-on called Mark Thread Done, which closes the thread and applies a prefix. Works well, even respecting the original thread prefix.
However, I really need the reporting system to assign a prefix to the new thread. Visually it is much easier for us to see which reports are unresolved and in addition, sorting by prefix is a great way to bring unresolved reports into one place.
Am I missing a setting that allows this? Setting a default and required thread prefix does nothing, since the reporting system bypasses the usual thread creation mechanism.
It can't be all that hard to do, can it? I could hard-code it into a template temporarily (since I know the prefix ID). Just don't know how/where to start, since I don't code anymore if I can help it.