Both in the create/modify page, and for specific tickets.
One can argue that there should be various options or whatever for sorting and make this way too complex... but I'm used to grouping label types by prefixes anyway, so having at least some sort of grouping system is very desirable to me. Having one ticket have
[AREA-Infrastructure] [TYPE-Bug] and the next
[TYPE-Bug] [AREA-Infrastructure] is awful.
Doesn't look too hard, just adding an
order_by in some database lookups or, worst case, sorting the results before feeding them into the templates. If you agree this is desirable I'll try to whip up a patch.