diff --git a/gui-lib/framework/private/main.rkt b/gui-lib/framework/private/main.rkt
index 09a4318f..72650ccb 100644
--- a/gui-lib/framework/private/main.rkt
+++ b/gui-lib/framework/private/main.rkt
@@ -390,6 +390,7 @@
               cases
                  instantiate super-instantiate
                syntax/loc quasisyntax/loc
+               datum-case
                match match* match-let match-let* match-letrec
                
                λ lambda let let* letrec recur