diff --git a/dlls/winemac.drv/cocoa_window.h b/dlls/winemac.drv/cocoa_window.h
index 1d7b31007f57706a8de6f638ca6b388dc61f4740..0f4e5b448361cbea370aa6ee4fd136d096c2df2e 100644
--- a/dlls/winemac.drv/cocoa_window.h
+++ b/dlls/winemac.drv/cocoa_window.h
@@ -19,6 +19,7 @@
  */
 
 #import <AppKit/AppKit.h>
+#import <QuartzCore/QuartzCore.h>
 
 
 @class WineEventQueue;
@@ -81,6 +82,8 @@ @interface WineWindow : NSPanel <NSWindowDelegate>
     BOOL ignore_windowDeminiaturize;
     BOOL ignore_windowResize;
     BOOL fakingClose;
+
+    CAShapeLayer* contentViewMaskLayer;
 }
 
 @property (retain, readonly, nonatomic) WineEventQueue* queue;