Subrepos are listed in a seemingly-randomized order in the Repository Registry
The current ordering doesn't appear to make any sense; it is neither alphabetized nor sorted according to .hgsub or .hgsubstate.
I would prefer that the sorting be as it is in .hgsub.
Drag and drop doesn't really make sense for this because updating to changesets which have more or fewer subrepos than the one that the manual sorting was done on could cause some degree of confusion, specifically the potential issue of new subrepos being added at the bottom when they are better placed closer to related subrepos. Things like this are easily expressed through .hgsub.