diff --git a/src/widgets/kernel/qsizepolicy.h b/src/widgets/kernel/qsizepolicy.h
index 41adf5c58a..5b236d6e44 100644
--- a/src/widgets/kernel/qsizepolicy.h
+++ b/src/widgets/kernel/qsizepolicy.h
@@ -45,6 +45,7 @@ class Q_WIDGETS_EXPORT QSizePolicy
 {
     Q_GADGET
     Q_ENUMS(Policy)
+    Q_FLAGS(ControlTypes)
 
 public:
     enum PolicyFlag {