Even though the claim from the headline is *slightly* corrected in the text, "Snow White Was The First Full-Length Color Movie With Sound" is a very incorrect statement.

Snow White was certainly the biggest hit of a film to be in color up to that time in early 1938, and certainly the first feature-length animated sound film in color. Moreover, its success is the primary reason The Wizard of Oz was made in three-step Technicolor, as it seemed to point to a potential market for a live-action Technicolor fantasy film.

However, there had already been dozens of Hollywood films - hits, flops, and otherwise - made in color and with sound between 1929 and 1939, when The Wizard of Oz came out. Warner Bros' On with the Show! (1929) was the first. There's a bunch more sound films in what was then two-strip Technicolor made up to 1933's Mystery of the Wax Museum (a good movie, remade as the 3D House of Wax in 1953). The studios at first thought audiences would take to color like they did to sound, but the Great Depression and increasing audience disinterest in the unrealistic red-green tones of two-strip Technicolor turned studios away from color films outside of short-subjects.

The first feature film made in the same three-strip Technicolor process as The Wizard of Oz was Becky Sharp (1935), an RKO release starring Miriam Hopkins. It's not generally recognized as such to laypeople because it's, unfortunately, not a good movie. Key pre-Snow White and pre-Oz hit three-strip Technicolor films (all of which were produced with sound, to be clear) include The Trail of the Lonesome Pine (1936) with Fred MacMurray and the original A Star is Born (1937) with Janet Gaynor. The Adventures of Robin Hood, starring Errol Flynn, was a huge Technicolor hit for Warner Bros. in 1938. It came out after Snow White and while Oz was in pre-production.

Oz's erroneous rep as a "pioneer of color movies" is a designation it got from being one of the first major movies shown on TV in color, in 1956.