diff --git a/Cocoa/Document.xib b/Cocoa/Document.xib
index 1f78d4a..1b93456 100644
--- a/Cocoa/Document.xib
+++ b/Cocoa/Document.xib
@@ -56,7 +56,7 @@
         </customObject>
         <customObject id="-1" userLabel="First Responder" customClass="FirstResponder"/>
         <customObject id="-3" userLabel="Application" customClass="NSObject"/>
-        <window title="Window" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" releasedWhenClosed="NO" visibleAtLaunch="NO" animationBehavior="default" tabbingMode="disallowed" id="xOd-HO-29H" userLabel="Window">
+        <window title="Window" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" releasedWhenClosed="NO" visibleAtLaunch="NO" animationBehavior="default" tabbingMode="disallowed" id="xOd-HO-29H" userLabel="Window" customClass="GBWindow">
             <windowStyleMask key="styleMask" titled="YES" closable="YES" miniaturizable="YES" resizable="YES"/>
             <windowCollectionBehavior key="collectionBehavior" fullScreenPrimary="YES"/>
             <rect key="contentRect" x="0.0" y="0.0" width="160" height="144"/>
diff --git a/Cocoa/GBWindow.h b/Cocoa/GBWindow.h
new file mode 100644
index 0000000..f391e07
--- /dev/null
+++ b/Cocoa/GBWindow.h
@@ -0,0 +1,5 @@
+#import <Cocoa/Cocoa.h>
+
+@interface GBWindow : NSWindow
+
+@end
diff --git a/Cocoa/GBWindow.m b/Cocoa/GBWindow.m
new file mode 100644
index 0000000..4b4e273
--- /dev/null
+++ b/Cocoa/GBWindow.m
@@ -0,0 +1,22 @@
+#import "GBWindow.h"
+
+@interface NSWindow(private)
+- (void)_zoomFill:(id)sender;
+@end
+
+/*
+   For some reason, Apple replaced the alt + zoom button behavior to be "fill" rather than zoom.
+   I don't like that. It prevents SameBoy's integer scaling from working. Let's restore it.
+*/
+
+@implementation GBWindow
+- (void)_zoomFill:(id)sender
+{
+    if (sender == [self standardWindowButton:NSWindowZoomButton] &&
+        (self.currentEvent.modifierFlags & NSEventModifierFlagOption)) {
+        [self zoom:sender];
+        return;
+    }
+    [super _zoomFill:sender];
+}
+@end