Right now, if you "duplicate" a market, it picks one group (I think the most recently added group) and only gives the new market that one group, rather than all of them. This is extremely annoying when trying to create sets of markets about similar events in the same category. (And can lead to markets not being put in the relevant groups when duplicated by people who don't realise this bug exists.)

This is a follow-up (with some changes) to /IsaacKing/will-duplicating-a-market-actually