TV Azteca was found at channel 20. At last what seemed to be the right movie poster was found in my book Carteles de la epoca de oro del cine mexicano/Poster Art From the Golden Age of Mexican Cinema to be able to tell from the caricature that the movie engrossing us is "Tal para cual" (we were pretty sure that we were seeing Jorge Negrete, but weren't so sure about whether that was Luis Aguilar). No end-credits were shown. I love this shrine to Mexican movies.