When I'm in my night phase and ready to play a Changeling so I can gain a thing, I can only click on the cards in play. It would be nice if I could also click on cards/piles in the supply to gain stuff.
Agreed. I have a similar issue for Duchess, where my mouse pointer instinctevely goes towards the Duchess pile whenever I want to gain one via her own ability. Pilgrimage might be another case, where a crowded in-play area might make a selection physically difficult.
OTOH, player confusion might be increased when they see little '+' crosses on supply piles, thinking they are still in the buy phase. But for Changeling that is probably not a problem.
This seemed counter-intuitive to me, too.