diff --git a/Source/OpenTK/Platform/MacOS/AglContext.cs b/Source/OpenTK/Platform/MacOS/AglContext.cs
index 36872054..c2bf34e9 100644
--- a/Source/OpenTK/Platform/MacOS/AglContext.cs
+++ b/Source/OpenTK/Platform/MacOS/AglContext.cs
@@ -125,10 +125,14 @@ namespace OpenTK.Platform.MacOS
             // Choose a pixel format with the attributes we specified.
             if (fullscreen)
             {
-                IntPtr gdevice;
-    
+				IntPtr gdevice;
+				IntPtr cgdevice = GetQuartzDevice(carbonWindow);
+
+				if (cgdevice == IntPtr.Zero)
+					cgdevice = QuartzDisplayDeviceDriver.MainDisplay;
+
                 OSStatus status = Carbon.API.DMGetGDeviceByDisplayID(
-                    QuartzDisplayDeviceDriver.MainDisplay, out gdevice, false);
+                    cgdevice, out gdevice, false);
                 
                 if (status != OSStatus.NoError)
                     throw new MacOSException(status, "DMGetGDeviceByDisplayID failed.");
@@ -177,6 +181,26 @@ namespace OpenTK.Platform.MacOS
             Debug.Print("context: {0}", Handle.Handle);
         }
 
+		private IntPtr GetQuartzDevice(CarbonWindowInfo carbonWindow)
+		{
+			IntPtr windowRef = carbonWindow.WindowRef;
+
+			if (CarbonGLNative.WindowRefMap.ContainsKey(windowRef) == false)
+				return IntPtr.Zero;
+
+			WeakReference nativeRef = CarbonGLNative.WindowRefMap[windowRef];
+			if (nativeRef.IsAlive == false)
+				return IntPtr.Zero;
+
+			CarbonGLNative window = nativeRef.Target as CarbonGLNative;
+
+			if (window == null)
+				return IntPtr.Zero;
+
+			return QuartzDisplayDeviceDriver.HandleTo(window.TargetDisplayDevice);
+
+		}
+
         void SetBufferRect(CarbonWindowInfo carbonWindow)
         {
             if (carbonWindow.IsControl == false)
diff --git a/Source/OpenTK/Platform/MacOS/CarbonGLNative.cs b/Source/OpenTK/Platform/MacOS/CarbonGLNative.cs
index d4c65a92..47044bfc 100644
--- a/Source/OpenTK/Platform/MacOS/CarbonGLNative.cs
+++ b/Source/OpenTK/Platform/MacOS/CarbonGLNative.cs
@@ -53,6 +53,7 @@ namespace OpenTK.Platform.MacOS
         Rectangle bounds, windowedBounds, clientRectangle;
         bool mIsDisposed = false;
 		bool mExists = true;
+		DisplayDevice mDisplayDevice;
 
         WindowAttributes mWindowAttrib;
         WindowClass mWindowClass;
@@ -65,9 +66,16 @@ namespace OpenTK.Platform.MacOS
 
         #endregion
 
-        #region Constructors
+		#region AGL Device Hack
 
-        static CarbonGLNative()
+		static internal Dictionary<IntPtr, WeakReference> WindowRefMap { get { return mWindows; } }
+		internal DisplayDevice TargetDisplayDevice { get { return mDisplayDevice; } }
+
+		#endregion
+
+		#region Constructors
+
+		static CarbonGLNative()
         {
             Application.Initialize();
         }
@@ -93,6 +101,8 @@ namespace OpenTK.Platform.MacOS
                 WindowAttributes.StandardDocument | WindowAttributes.StandardHandler |
                 WindowAttributes.InWindowMenu | WindowAttributes.LiveResize,
                 new Rect((short)x, (short)y, (short)width, (short)height));
+
+			mDisplayDevice = device;
         }
 
         #endregion
diff --git a/Source/OpenTK/Platform/MacOS/QuartzDisplayDeviceDriver.cs b/Source/OpenTK/Platform/MacOS/QuartzDisplayDeviceDriver.cs
index 26f873cd..3f3e65af 100644
--- a/Source/OpenTK/Platform/MacOS/QuartzDisplayDeviceDriver.cs
+++ b/Source/OpenTK/Platform/MacOS/QuartzDisplayDeviceDriver.cs
@@ -106,6 +106,15 @@ namespace OpenTK.Platform.MacOS
             }
         }
 
+
+		internal static IntPtr HandleTo(DisplayDevice displayDevice)
+		{
+			if (displayMap.ContainsKey(displayDevice))
+				return displayMap[displayDevice];
+			else
+				return IntPtr.Zero;
+		}
+
         #region IDisplayDeviceDriver Members
 
         Dictionary<IntPtr, IntPtr> storedModes = new Dictionary<IntPtr, IntPtr>();
@@ -173,5 +182,6 @@ namespace OpenTK.Platform.MacOS
         }
 
         #endregion
-    }
+
+	}
 }