“The play opened at 8:40 sharp and closed at 10:40 dull” (Broadway saying)

The shortest review of a play is credited to Heywood Broun (1888-1939), who allegedly wrote this simple dismissal of the play’s proceedings:
 
“It opened at 8:30 sharp and closed at 10:40 dull.”
 
Various accounts have the time as an 8:40 opening or a 10:30 or 11:10 closing. The line has been cited in print since at least 1946, but the identity of the play is unknown.
 
       
Wikipedia: Heywood Broun
Heywood Campbell Broun, Jr. ( /ˈbruːn/; December 7, 1888 – December 18, 1939) was an American journalist. He worked as a sportswriter, newspaper columnist, and editor in New York City. He founded the American Newspaper Guild, now known as The Newspaper Guild. Born in Brooklyn, New York, he is best remembered for his writing on social issues and his championing of the underdog. He believed that journalists could help right wrongs, especially social ills.
 
Old Fulton NY Post Cards
23 May 1946, New York (NY) Post, Daily Magazine Section, pg. 58, col. 3:
More of Heywood Broun: One of the shortest drama reviews on record—“It opened at 8:30 sharp and closed at 10:40 dull.”
 
25 May 1946, Augusta (GA) Chronicle, “Tales of The Town” by Walter Winchell, pg. 4, col. 5:
One of the briefest drama reviews on record was written by Heywood Broun, who wrote of a play (that shall be nameless): “It opened at 8:40 sharp and closed at 10: 40 dull.”
 
2 May 1960, Rockford (IL) Register-Republic, “Earl’s Pearls” by Earl Wilson, pg. 2A, col. 4:
People who have attended some local civic meetings complain that they open at 7:30 sharp and close at 10:30 dull.
     
27 July 1964, Aberdeen (SD) American-News, “Earl Wilson on Tour” by Earl Wilson, pg. 4, col. 5:
REMEMBERED QUOTE: Heywood Broun once described a bad show: “It opened at 8:40 sharp, and closed at 11:10 dull.”
 
3 February 1967, Winona (MN) Daily News, “It Happened Last Night” by Earl Wilson, pg. 4, col. 2:
REMEMBERED QUOTE: Heywood Broun once reviewed a play: “It opened at 8:40 sharp and closed at 11:10 dull.”
 
Google Books
Broadway Babylon:
Glamour, glitz, and gossip on the Great White Way
By Boze Hadleigh
New York, NY: Back Stage Books
2007
Pg. 65:
“The play opened at 8:40 sharp and closed at 10:40 dull.” — HEYWOOD BROUN on a Broadway comedy