In this post about Robert Altman's The Long Goodbye, I wrote about the big musical joke in John Williams' score, which is that there's only one theme in the movie and it's heard in every conceivable form (even when Marlowe rings a doorbell, the doorbell plays the movie's theme song). I mentioned that this was a parody of the incessant plugging of movie title songs in the late '60s. But it occurs to me that it might also be a nod to a specific movie, Out of the Past. Roy Webb's score has more than one theme somewhere in there, but the main theme is heard a lot and in all kinds of different forms: when Robert Mitchum goes to a nightclub, the band is playing the movie's theme song; when Jane Greer puts on a record, there it is again. The Long Goodbye was a film noir tribute before such tributes were cool -- and it captures the messiness and freakish supporting characters of noir in a way that the tidier, more refined and humorless Chinatown can't do -- so I wouldn't be surprised if this was a conscious reference.
Roy Webb, by the way, was a pretty entertaining composer; he never made the big time among film composers, but because he was at RKO, the quirkiest of Hollywood studios, he got to score a lot of interesting movies: everything from I Married A Witch to the Val Lewton films to Alfred Hitchcock's Notorious to a boatload of films noirs. He matched RKO's tough, punchy style with tough, punchy scores that usually also included at least one big romantic string theme for the opening credits. Basically, he wrote high-quality B-movie music, but that's perfect for movies like Cat People and Out of the Past and Murder My Sweet, which are essentially B-movie material raised to A-level by imagination and energy, rather than big money or big stars.
Before Webb came out to Hollywood, he was a Broadway orchestrator who orchestrated many Rodgers and Hart shows in the '20s; most of his orchestrations are lost, but his surviving orchestrations for shows like A Connecticut Yankee and Chee-Chee are knockouts, every bit as good as the work of a Robert Russell Bennett.