I can't use the shift key when dismounting a horse, boat, or minecart so I've got stuck in them with no way out unless a player breaks the boat/minecart or the horse goes in water. I can use it just fine when holding down shift when using chests though. It doesn't matter if I change the shift key to another key- those functions still don't work, and the new "shift key" doesn't work when using chests, but shift does.