Design for Living truly excels in the casting department. It's four primary players are Fredric March, Gary Cooper, Miriam Hopkins and Edward Everett Horton, and each of them is absolutely perfect in their role -- Fredric March as the snarky playwright, Gary Cooper as the furniture-smashing painter, Miriam Hopkins as the classy minx and Edward Everett Horton as the straight-laced yet flustered milquetoast. March and Cooper play off one another extremely well, exhibiting both camaraderie and jealousy. Both also demonstrate great chemistry with Hopkins in the romantic scenes (for her part, Miriam displays significant presence while on screen). Finally, Horton's part as the jealous friend seems at first like an unusual heel turn for him, but ultimately works out just as well.
Definitely give this one a watch if you get the chance.