diff --git a/gdk/quartz/GdkQuartzNSWindow.c b/gdk/quartz/GdkQuartzNSWindow.c
index 3445e3eaeb..3927d9d35e 100644
--- a/gdk/quartz/GdkQuartzNSWindow.c
+++ b/gdk/quartz/GdkQuartzNSWindow.c
@@ -252,7 +252,7 @@
                              screen:screen];
 
   [self setAcceptsMouseMovedEvents:YES];
-  [self setDelegate:self];
+  [self setDelegate:(id)self];
   [self setReleasedWhenClosed:YES];
 
   return self;