The FDB-1 was one of the last biplane fighters developed, first flown
in December 1938. It was also one of the cleanest and most beautiful
biplane fighters, with an all-round vision, closed cockpit,
retractable landing gear, and a gulled upper wing. But it was also
clearly an obsolete concept. One built.
I did not know this but Canada(God bless her) designed and built a biplane fighter in 1938. It was built by Canadian Car Foundry, and called the Gregor FDB-1. I imagine it stemmed from CCF building Grumman G-23 Goblins. Only one FDB-1 was built and was evaluated in early 1939 as obsolete. For some reason and somehow, the one example appears to have ended up in the Chinese Air Force in WW2!!!