Here's sally Milgrim's 1994 obit from the NY TIMES :
"Sally Milgrim, a designer of women's apparel who with her husband, Charles, owned the Milgrim fashion store on 57th Street for many years, died on Saturday at St. Francis Barry Nursing and Rehabilitative Center in Miami. She was 103 years old.
Mrs. Milgrim began as a custom designer on the Lower East Side in Manhattan in the early 1920's, moved briefly to Broadway and 72d Street and in 1927 opened the store on 57th Street near Fifth Avenue, where it became one of the area's best-known custom and specialty stores from the 1930's through the 1950's. The Milgrim shop emphasized quality dresses that were ready to wear at a time when high fashion was still a world of made-to-order styles and custom-made tailored suits.
One of Mrs. Milgrim's best-known designs was a light blue gown worn by Eleanor Roosevelt to her husband's first inaugural ball, in 1933. Mrs. Milgrim also made dresses for the entertainers Marilyn Miller, Ethel Merman, Pearl White, Mary Pickford and others.
At one point there were also Milgrim stores in Detroit, Cleveland, Columbus, Chicago, East Orange, N.J., White Plains, Miami and Palm Beach. Mrs. Milgrim also sold a wholesale dress collection to stores throughout the country.
She retired in 1960. Her husband died in 1967. The last Milgrim store, in Cleveland, was closed in 1990.
Mrs. Milgrim is survived by two sons, Franklin of Miami and Paul of Detroit, a brother, Louis Knobel of Fort Lauderdale, Fla., five grandchildren and six great-grandchildren."
No mention of a Polish grandfather, but definitely a store in White Plains. But it the dates indicate that this dress would have come after Sally's retirement.
Hollis