In a trade dress case, Polaroid argues that Fujifilm is estopped from arguing that its trade dress is functional because Fujifilm got a design patent on a nearly identical design:
https://www.scribd.com/document/704650539/Fujifilm-v-Polaroid-MSJ-Opp-n
Two things:
1) No, design patents are NOT evidence of trade dress functionality: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2710661
2) How did Fujifilm get this patent?