diff --git a/src/posix/cocoa/i_video.mm b/src/posix/cocoa/i_video.mm
index 521f0648f..fb835f9db 100644
--- a/src/posix/cocoa/i_video.mm
+++ b/src/posix/cocoa/i_video.mm
@@ -251,6 +251,11 @@ namespace
 	return [self.class.layerClass layer];
 }
 
+-(BOOL) isOpaque
+{
+	return YES;
+}
+
 @end