diff --git a/include/osgViewer/api/Carbon/GraphicsHandleCarbon b/include/osgViewer/api/Carbon/GraphicsHandleCarbon
new file mode 100644
index 000000000..c9b480cb5
--- /dev/null
+++ b/include/osgViewer/api/Carbon/GraphicsHandleCarbon
@@ -0,0 +1,50 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2009 Robert Osfield 
+ *
+ * This library is open source and may be redistributed and/or modified under  
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
+ * OpenSceneGraph Public License for more details.
+*/
+
+#ifndef OSGVIEWER_GRAPHICSHANDLECARBON
+#define OSGVIEWER_GRAPHICSHANDLECARBON 1
+
+#include <osgViewer/Export>
+
+#include <Carbon/Carbon.h>
+#include <AGL/agl.h>
+
+
+namespace osgViewer
+{
+
+/** Class to encapsulate platform-specific OpenGL context handle variables.
+  * Derived osg::GraphicsContext classes can inherit from this class to
+  * share OpenGL resources.*/
+
+class OSGVIEWER_EXPORT GraphicsHandleCarbon
+{
+    public:
+    
+        GraphicsHandleCarbon():
+            _context(0) {}
+
+        /** Set native AGL graphics context.*/        
+        inline void setAGLContext(AGLContext context) { _context = context; }
+
+        /** Get native AGL graphics context.*/        
+        inline AGLContext getAGLContext() const { return _context; }
+
+    protected:
+        
+        AGLContext      _context;
+};
+
+}
+
+#endif
diff --git a/include/osgViewer/api/Carbon/GraphicsWindowCarbon b/include/osgViewer/api/Carbon/GraphicsWindowCarbon
index 3a72a7890..1a7cb02ae 100644
--- a/include/osgViewer/api/Carbon/GraphicsWindowCarbon
+++ b/include/osgViewer/api/Carbon/GraphicsWindowCarbon
@@ -22,12 +22,12 @@
 #if defined (__APPLE__) && (!__LP64__)
 
 #include <osgViewer/GraphicsWindow>
-#include <Carbon/Carbon.h>
-#include <AGL/agl.h>
+#include <osgViewer/api/Carbon/GraphicsHandleCarbon>
+
 namespace osgViewer
 {
 
-class GraphicsWindowCarbon : public osgViewer::GraphicsWindow
+class GraphicsWindowCarbon : public osgViewer::GraphicsWindow, public osgViewer::GraphicsHandleCarbon
 {
     public:
 
@@ -137,9 +137,6 @@ class GraphicsWindowCarbon : public osgViewer::GraphicsWindow
         /// install the standard os-eventhandler
         void installEventHandler();
         
-        /// get the AGL context
-        AGLContext getAGLContext() { return _context; }
-        
         // get the pixelformat
         AGLPixelFormat getAGLPixelFormat() { return _pixelFormat; }
         
@@ -159,7 +156,6 @@ class GraphicsWindowCarbon : public osgViewer::GraphicsWindow
 
         bool            _ownsWindow;
         WindowRef       _window;
-        AGLContext      _context;
         AGLPixelFormat  _pixelFormat;
         
         int             _windowTitleHeight;    
diff --git a/include/osgViewer/api/Carbon/PixelBufferCarbon b/include/osgViewer/api/Carbon/PixelBufferCarbon
index ad5183314..5880450fe 100644
--- a/include/osgViewer/api/Carbon/PixelBufferCarbon
+++ b/include/osgViewer/api/Carbon/PixelBufferCarbon
@@ -19,16 +19,13 @@
 #if defined (__APPLE__) && (!__LP64__)
 
 #include <osg/GraphicsContext>
-#include <osgViewer/Export>
-
-#include <Carbon/Carbon.h>
-#include <AGL/agl.h>
+#include <osgViewer/api/Carbon/GraphicsHandleCarbon>
 
 
 namespace osgViewer
 {
 
-class OSGVIEWER_EXPORT PixelBufferCarbon : public osg::GraphicsContext
+class OSGVIEWER_EXPORT PixelBufferCarbon : public osg::GraphicsContext, public osgViewer::GraphicsHandleCarbon
 {
     public:
 
@@ -37,8 +34,7 @@ class OSGVIEWER_EXPORT PixelBufferCarbon : public osg::GraphicsContext
             _initialized(false),
             _realized(false),
             _pixelformat(0),
-            _pbuffer(0),
-            _context(0)
+            _pbuffer(0)
         {
             _traits = traits;
 
@@ -91,10 +87,8 @@ class OSGVIEWER_EXPORT PixelBufferCarbon : public osg::GraphicsContext
 
         /** Swap the front and back buffers.*/
         virtual void swapBuffersImplementation();
-        
+       
         static AGLPixelFormat createPixelFormat(osg::GraphicsContext::Traits* traits);
-        
-        AGLContext getAGLContext() { return _context; }
 
     public:
     
@@ -112,9 +106,7 @@ class OSGVIEWER_EXPORT PixelBufferCarbon : public osg::GraphicsContext
         bool            _realized;
         
         AGLPixelFormat    _pixelformat;
-        AGLPbuffer        _pbuffer;
-        AGLContext        _context;
-        
+        AGLPbuffer        _pbuffer;        
 };
 
 }
diff --git a/include/osgViewer/api/Win32/GraphicsHandleWin32 b/include/osgViewer/api/Win32/GraphicsHandleWin32
new file mode 100644
index 000000000..f6ac8fa28
--- /dev/null
+++ b/include/osgViewer/api/Win32/GraphicsHandleWin32
@@ -0,0 +1,127 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2009 Robert Osfield 
+ *
+ * This library is open source and may be redistributed and/or modified under  
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
+ * OpenSceneGraph Public License for more details.
+*/
+
+#ifndef OSGVIEWER_GRAPHICSHANDLEWIN32
+#define OSGVIEWER_GRAPHICSHANDLEWIN32 1
+
+#include <osgViewer/Export>
+
+#ifndef _WIN32_WINNT
+#define _WIN32_WINNT    0x0500
+#endif
+#include <windows.h>
+
+namespace osgViewer
+{
+
+/** Class to encapsulate platform-specific OpenGL context handle variables.
+  * Derived osg::GraphicsContext classes can inherit from this class to
+  * share OpenGL resources.*/
+
+class OSGVIEWER_EXPORT GraphicsHandleWin32
+{
+    public:
+    
+        GraphicsHandleWin32():
+            _hwnd(0),
+            _hdc(0),
+            _hglrc(0) {}
+
+        /** Set native window.*/        
+        inline void setHWND(HWND hwnd) { _hwnd = hwnd; }
+
+        /** Get native window.*/        
+        inline HWND getHWND() const { return _hwnd; }
+
+        /** Set device context.*/        
+        inline void setHDC(HDC hdc) { _hdc = hdc; }
+
+        /** Get device context.*/        
+        inline HDC getHDC() const { return _hdc; }
+
+        /** Set native OpenGL graphics context.*/        
+        inline void setWGLContext(HGLRC hglrc) { _hglrc = hglrc; }
+
+        /** Get native OpenGL graphics context.*/        
+        inline HGLRC getWGLContext() const { return _hglrc; }
+     
+    protected:
+        
+        HWND            _hwnd;
+        HDC             _hdc;
+        HGLRC           _hglrc;
+    
+};
+
+}
+
+
+// Definitions required to create an OpenGL pixel format, from the WGL_ARB_pixel_format specification document.
+// See http://www.opengl.org/registry/specs/ARB/wgl_pixel_format.txt
+
+#ifndef WGL_ARB_pixel_format
+#define WGL_ARB_pixel_format 1
+#define WGL_NUMBER_PIXEL_FORMATS_ARB        0x2000
+#define WGL_DRAW_TO_WINDOW_ARB              0x2001
+#define WGL_DRAW_TO_BITMAP_ARB              0x2002
+#define WGL_ACCELERATION_ARB                0x2003
+#define WGL_NEED_PALETTE_ARB                0x2004
+#define WGL_NEED_SYSTEM_PALETTE_ARB         0x2005
+#define WGL_SWAP_LAYER_BUFFERS_ARB          0x2006
+#define WGL_SWAP_METHOD_ARB                 0x2007
+#define WGL_NUMBER_OVERLAYS_ARB             0x2008
+#define WGL_NUMBER_UNDERLAYS_ARB            0x2009
+#define WGL_TRANSPARENT_ARB                 0x200A
+#define WGL_TRANSPARENT_RED_VALUE_ARB       0x2037
+#define WGL_TRANSPARENT_GREEN_VALUE_ARB     0x2038
+#define WGL_TRANSPARENT_BLUE_VALUE_ARB      0x2039
+#define WGL_TRANSPARENT_ALPHA_VALUE_ARB     0x203A
+#define WGL_TRANSPARENT_INDEX_VALUE_ARB     0x203B
+#define WGL_SHARE_DEPTH_ARB                 0x200C
+#define WGL_SHARE_STENCIL_ARB               0x200D
+#define WGL_SHARE_ACCUM_ARB                 0x200E
+#define WGL_SUPPORT_GDI_ARB                 0x200F
+#define WGL_SUPPORT_OPENGL_ARB              0x2010
+#define WGL_DOUBLE_BUFFER_ARB               0x2011
+#define WGL_STEREO_ARB                      0x2012
+#define WGL_PIXEL_TYPE_ARB                  0x2013
+#define WGL_COLOR_BITS_ARB                  0x2014
+#define WGL_RED_BITS_ARB                    0x2015
+#define WGL_RED_SHIFT_ARB                   0x2016
+#define WGL_GREEN_BITS_ARB                  0x2017
+#define WGL_GREEN_SHIFT_ARB                 0x2018
+#define WGL_BLUE_BITS_ARB                   0x2019
+#define WGL_BLUE_SHIFT_ARB                  0x201A
+#define WGL_ALPHA_BITS_ARB                  0x201B
+#define WGL_ALPHA_SHIFT_ARB                 0x201C
+#define WGL_ACCUM_BITS_ARB                  0x201D
+#define WGL_ACCUM_RED_BITS_ARB              0x201E
+#define WGL_ACCUM_GREEN_BITS_ARB            0x201F
+#define WGL_ACCUM_BLUE_BITS_ARB             0x2020
+#define WGL_ACCUM_ALPHA_BITS_ARB            0x2021
+#define WGL_DEPTH_BITS_ARB                  0x2022
+#define WGL_STENCIL_BITS_ARB                0x2023
+#define WGL_AUX_BUFFERS_ARB                 0x2024
+#define WGL_NO_ACCELERATION_ARB             0x2025
+#define WGL_GENERIC_ACCELERATION_ARB        0x2026
+#define WGL_FULL_ACCELERATION_ARB           0x2027
+#define WGL_SWAP_EXCHANGE_ARB               0x2028
+#define WGL_SWAP_COPY_ARB                   0x2029
+#define WGL_SWAP_UNDEFINED_ARB              0x202A
+#define WGL_TYPE_RGBA_ARB                   0x202B
+#define WGL_TYPE_COLORINDEX_ARB             0x202C
+#define WGL_SAMPLE_BUFFERS_ARB              0x2041
+#define WGL_SAMPLES_ARB                     0x2042
+#endif
+
+#endif
diff --git a/include/osgViewer/api/Win32/GraphicsWindowWin32 b/include/osgViewer/api/Win32/GraphicsWindowWin32
index 88390a740..afcaaee65 100644
--- a/include/osgViewer/api/Win32/GraphicsWindowWin32
+++ b/include/osgViewer/api/Win32/GraphicsWindowWin32
@@ -20,16 +20,12 @@
 #define OSGVIEWER_GRAPHICSWINDOWWIN32 1
 
 #include <osgViewer/GraphicsWindow>
-
-#ifndef _WIN32_WINNT
-#define _WIN32_WINNT    0x0500
-#endif
-#include <windows.h>
+#include <osgViewer/api/Win32/GraphicsHandleWin32>
 
 namespace osgViewer
 {
 
-class OSGVIEWER_EXPORT GraphicsWindowWin32 : public osgViewer::GraphicsWindow
+class OSGVIEWER_EXPORT GraphicsWindowWin32 : public osgViewer::GraphicsWindow, public osgViewer::GraphicsHandleWin32
 {
     public:
 
@@ -103,14 +99,6 @@ class OSGVIEWER_EXPORT GraphicsWindowWin32 : public osgViewer::GraphicsWindow
             HWND    _hwnd;
             bool   _installEventHandler;
         };
-
-        /** Get native window.*/        
-        HWND getHWND() const { return _hwnd; }
-
-        HDC getHDC() const { return _hdc; }
-
-        /** Get native OpenGL graphics context.*/        
-        HGLRC getWGLContext() const { return _hglrc; }
         
     protected:
     
@@ -139,8 +127,7 @@ class OSGVIEWER_EXPORT GraphicsWindowWin32 : public osgViewer::GraphicsWindow
                                               unsigned int& extendedStyle );
         
         bool setPixelFormat();
-        HGLRC createContextImplementation();
-
+        
         void adaptKey( WPARAM wParam, LPARAM lParam, int& keySymbol, unsigned int& modifierMask );
                 
         void transformMouseXY(float& x, float& y);
@@ -149,9 +136,6 @@ class OSGVIEWER_EXPORT GraphicsWindowWin32 : public osgViewer::GraphicsWindow
 
         HCURSOR getOrCreateCursor(MouseCursor mouseShape);
         
-        HWND            _hwnd;
-        HDC             _hdc;
-        HGLRC           _hglrc;
         HCURSOR         _currentCursor;
         
         WNDPROC         _windowProcedure;
diff --git a/include/osgViewer/api/Win32/PixelBufferWin32 b/include/osgViewer/api/Win32/PixelBufferWin32
index 066edfa50..d82548065 100644
--- a/include/osgViewer/api/Win32/PixelBufferWin32
+++ b/include/osgViewer/api/Win32/PixelBufferWin32
@@ -19,18 +19,13 @@
 #ifndef OSGVIEWER_PIXELBUFFERWIN32
 #define OSGVIEWER_PIXELBUFFERWIN32 1
 
-#include <osgViewer/GraphicsWindow>
-
-#ifndef _WIN32_WINNT
-#define _WIN32_WINNT    0x0500
-#endif
-
-#include <windows.h>
+#include <osg/GraphicsContext>
+#include <osgViewer/api/Win32/GraphicsHandleWin32>
 
 namespace osgViewer
 {
 
-class OSGVIEWER_EXPORT PixelBufferWin32 : public osg::GraphicsContext
+class OSGVIEWER_EXPORT PixelBufferWin32 : public osg::GraphicsContext, public osgViewer::GraphicsHandleWin32
 {
     public:
 
@@ -62,24 +57,12 @@ class OSGVIEWER_EXPORT PixelBufferWin32 : public osg::GraphicsContext
 
         /** Swap the front and back buffers.*/
         virtual void swapBuffersImplementation();
-
-        /** Get native window.*/        
-        HWND getHWND() const { return _hwnd; }
-
-        HDC getHDC() const { return _hdc; }
-
-        /** Get native OpenGL graphics context.*/        
-        HGLRC getWGLContext() const { return _hglrc; }
-        
+       
         virtual void bindPBufferToTextureImplementation( GLenum /*buffer*/ );
         
     protected:
     
         void init();
-        
-        HWND            _hwnd;
-        HDC             _hdc;
-        HGLRC           _hglrc;
 
         bool            _initialized;
         bool            _valid;
diff --git a/include/osgViewer/api/X11/GraphicsHandleX11 b/include/osgViewer/api/X11/GraphicsHandleX11
new file mode 100644
index 000000000..fde7bb6f6
--- /dev/null
+++ b/include/osgViewer/api/X11/GraphicsHandleX11
@@ -0,0 +1,80 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2009 Robert Osfield 
+ *
+ * This library is open source and may be redistributed and/or modified under  
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
+ * OpenSceneGraph Public License for more details.
+*/
+
+#ifndef OSGVIEWER_GRAPHICSHANDLEX11
+#define OSGVIEWER_GRAPHICSHANDLEX11 1
+
+#include <osgViewer/Export>
+
+
+#if defined(OSG_GLES1_AVAILABLE) || defined(OSG_GLES2_AVAILABLE)
+    #define OSG_USE_EGL
+    #include <X11/X.h>
+    #include <X11/Xlib.h>
+    #include <X11/Xutil.h>
+    #include <EGL/egl.h>
+#else
+    #define GLX_GLXEXT_PROTOTYPES  1
+    #include <X11/X.h>
+    #include <X11/Xlib.h>
+    #include <X11/Xutil.h>
+    #include <GL/glx.h>
+    #ifndef GLX_VERSION_1_3
+        typedef XID GLXPbuffer;
+    #endif
+#endif
+
+namespace osgViewer
+{
+
+/** Class to encapsulate platform-specific OpenGL context handle variables.
+  * Derived osg::GraphicsContext classes can inherit from this class to
+  * share OpenGL resources.*/
+
+class OSGVIEWER_EXPORT GraphicsHandleX11
+{
+    public:
+    
+        GraphicsHandleX11():
+            _display(0),
+            _context(0) {}
+
+        /** Set X11 display.*/        
+        inline void setDisplay(Display* display) { _display = display; }
+
+        /** Get X11 display.*/        
+        inline Display* getDisplay() const { return _display; }
+
+        #ifdef OSG_USE_EGL
+            typedef EGLContext Context;
+            typedef EGLSurface Pbuffer;
+        #else
+            typedef GLXContext Context;
+            typedef GLXPbuffer Pbuffer;
+        #endif
+
+        /** Set native OpenGL graphics context.*/
+        inline void setContext(Context context) { _context = context; }
+
+        /** Get native OpenGL graphics context.*/        
+        inline Context getContext() const { return _context; }
+
+    protected:
+        
+        Display*        _display;
+        Context         _context;
+};
+
+}
+
+#endif
diff --git a/include/osgViewer/api/X11/GraphicsWindowX11 b/include/osgViewer/api/X11/GraphicsWindowX11
index d79733b16..5ce22845a 100644
--- a/include/osgViewer/api/X11/GraphicsWindowX11
+++ b/include/osgViewer/api/X11/GraphicsWindowX11
@@ -20,38 +20,23 @@
 #define OSGVIEWER_GRAPHICSWINDOWX11 1
 
 #include <osgViewer/GraphicsWindow>
-
-#define GLX_GLXEXT_PROTOTYPES  1
-
-#include <X11/X.h>
-#include <X11/Xlib.h>
-#include <X11/Xutil.h>
-
-#if defined(OSG_GLES1_AVAILABLE) || defined(OSG_GLES2_AVAILABLE) 
-    #define OSG_USE_EGL
-    #include <EGL/egl.h>
-#else
-    #include <GL/glx.h>
-#endif
-
+#include <osgViewer/api/X11/GraphicsHandleX11>
 
 #include <string.h>
 
 namespace osgViewer
 {
 
-class OSGVIEWER_EXPORT GraphicsWindowX11 : public osgViewer::GraphicsWindow
+class OSGVIEWER_EXPORT GraphicsWindowX11 : public osgViewer::GraphicsWindow, public osgViewer::GraphicsHandleX11
 {
     public:
 
         GraphicsWindowX11(osg::GraphicsContext::Traits* traits):
             _valid(false),
-            _display(0),
             _eventDisplay(0),
             _parent(0),
             _window(0),
             _visualInfo(0),
-            _context(0),
             #ifdef OSG_USE_EGL
             _eglDisplay(0),
             _eglSurface(0),
@@ -151,7 +136,6 @@ class OSGVIEWER_EXPORT GraphicsWindowX11 : public osgViewer::GraphicsWindow
     
         // X11 specific aces functions
 
-        Display* getDisplay() const { return _display; }
         Display* getEventDisplay() const { return _eventDisplay; }
         Display* getDisplayToUse() const ;
 
@@ -159,15 +143,6 @@ class OSGVIEWER_EXPORT GraphicsWindowX11 : public osgViewer::GraphicsWindow
         Window& getParent() { return _parent; }
         Window& getWindow() { return _window; }
 
-
-        #ifdef OSG_USE_EGL
-        typedef EGLContext Context;
-        #else
-        typedef GLXContext Context;
-        #endif
-
-        Context& getContext() { return _context; }
-
         Cursor getCurrentCursor() { return _currentCursor; }
 
     protected:
@@ -197,12 +172,10 @@ class OSGVIEWER_EXPORT GraphicsWindowX11 : public osgViewer::GraphicsWindow
         void flushKeyEvents();
         
         bool            _valid;
-        Display*        _display;
         Display*        _eventDisplay;
         Window          _parent;
         Window          _window;
         XVisualInfo*    _visualInfo;
-        Context         _context;
 
         #ifdef OSG_USE_EGL
         EGLDisplay      _eglDisplay;
diff --git a/include/osgViewer/api/X11/PixelBufferX11 b/include/osgViewer/api/X11/PixelBufferX11
index 346a064f4..e4555a674 100644
--- a/include/osgViewer/api/X11/PixelBufferX11
+++ b/include/osgViewer/api/X11/PixelBufferX11
@@ -19,18 +19,13 @@
 #ifndef OSGVIEWER_PIXELBUFFERX11
 #define OSGVIEWER_PIXELBUFFERX11 1
 
-#include <osgViewer/api/X11/GraphicsWindowX11>
-
-#ifndef OSG_USE_EGL
-    #ifndef GLX_VERSION_1_3
-        typedef XID GLXPbuffer;
-    #endif
-#endif
+#include <osg/GraphicsContext>
+#include <osgViewer/api/X11/GraphicsHandleX11>
 
 namespace osgViewer
 {
 
-class OSGVIEWER_EXPORT PixelBufferX11 : public osg::GraphicsContext
+class OSGVIEWER_EXPORT PixelBufferX11 : public osg::GraphicsContext, public osgViewer::GraphicsHandleX11
 {
     public:
 
@@ -69,19 +64,8 @@ class OSGVIEWER_EXPORT PixelBufferX11 : public osg::GraphicsContext
     public:
     
         // X11 specific aces functions
-
-        Display* getDisplay() const { return _display; }
         
-        #ifdef OSG_USE_EGL
-            typedef EGLContext Context;
-            typedef EGLSurface Pbuffer;
-        #else
-            typedef GLXContext Context;
-            typedef GLXPbuffer Pbuffer;
-        #endif
-
         Pbuffer& getPbuffer() { return _pbuffer; }
-        Context& getContext() { return _context; }
 
     protected:
     
@@ -92,10 +76,8 @@ class OSGVIEWER_EXPORT PixelBufferX11 : public osg::GraphicsContext
         void init();
 
         bool            _valid;
-        Display*        _display;
         Pbuffer         _pbuffer;
         XVisualInfo*    _visualInfo;
-        Context         _context;
 
         bool            _initialized;
         bool            _realized;
diff --git a/src/osgViewer/CMakeLists.txt b/src/osgViewer/CMakeLists.txt
index 38779318d..53cc4305d 100644
--- a/src/osgViewer/CMakeLists.txt
+++ b/src/osgViewer/CMakeLists.txt
@@ -53,6 +53,7 @@ IF(WIN32)
     ENDIF()
 
     SET(LIB_PUBLIC_HEADERS ${LIB_PUBLIC_HEADERS}
+        ${HEADER_PATH}/api/Win32/GraphicsHandleWin32
         ${HEADER_PATH}/api/Win32/GraphicsWindowWin32
         ${HEADER_PATH}/api/Win32/PixelBufferWin32
     )
@@ -84,6 +85,7 @@ ELSE()
     ELSEIF(${OSG_WINDOWING_SYSTEM} STREQUAL "Carbon")
         ADD_DEFINITIONS(-DUSE_DARWIN_CARBON_IMPLEMENTATION)
         SET(LIB_PUBLIC_HEADERS ${LIB_PUBLIC_HEADERS} 
+            ${HEADER_PATH}/api/Carbon/GraphicsHandleCarbon
             ${HEADER_PATH}/api/Carbon/GraphicsWindowCarbon
             ${HEADER_PATH}/api/Carbon/PixelBufferCarbon
         )
@@ -109,6 +111,7 @@ ELSE()
         ENDIF()
 
         SET(LIB_PUBLIC_HEADERS ${LIB_PUBLIC_HEADERS}
+            ${HEADER_PATH}/api/X11/GraphicsHandleX11
             ${HEADER_PATH}/api/X11/GraphicsWindowX11
             ${HEADER_PATH}/api/X11/PixelBufferX11
         )
@@ -117,7 +120,7 @@ ELSE()
             GraphicsWindowX11.cpp 
             PixelBufferX11.cpp
         )
-
+        
         IF(OSGVIEWER_USE_XRANDR)
             ADD_DEFINITIONS(-DOSGVIEWER_USE_XRANDR)
             SET(LIB_PRIVATE_HEADERS ${LIB_PRIVATE_HEADERS} ${XRANDR_INCLUDE_DIRS} )
diff --git a/src/osgViewer/GraphicsWindowCarbon.cpp b/src/osgViewer/GraphicsWindowCarbon.cpp
index 3cbe741d9..7afe7a0de 100644
--- a/src/osgViewer/GraphicsWindowCarbon.cpp
+++ b/src/osgViewer/GraphicsWindowCarbon.cpp
@@ -398,18 +398,12 @@ bool GraphicsWindowCarbon::realizeImplementation()
     // create the context
     AGLContext sharedContextCarbon = NULL;
     
-    GraphicsWindowCarbon* graphicsWindowCarbon = dynamic_cast<GraphicsWindowCarbon*>(_traits->sharedContext);
-    if (graphicsWindowCarbon) 
+    GraphicsHandleCarbon* graphicsHandleCarbon = dynamic_cast<GraphicsHandleCarbon*>(_traits->sharedContext);
+    if (graphicsHandleCarbon) 
     {
-        sharedContextCarbon = graphicsWindowCarbon->getAGLContext();
-    }
-    else
-    {
-        PixelBufferCarbon* pixelbuffer = dynamic_cast<PixelBufferCarbon*>(_traits->sharedContext);
-        if (pixelbuffer) {
-            sharedContextCarbon = pixelbuffer->getAGLContext();
-        }
+        sharedContextCarbon = graphicsHandleCarbon->getAGLContext();
     }
+
     _context = aglCreateContext (_pixelFormat, sharedContextCarbon);
 
 
diff --git a/src/osgViewer/GraphicsWindowWin32.cpp b/src/osgViewer/GraphicsWindowWin32.cpp
index 14e3d758f..6309a4f95 100644
--- a/src/osgViewer/GraphicsWindowWin32.cpp
+++ b/src/osgViewer/GraphicsWindowWin32.cpp
@@ -1029,10 +1029,7 @@ osgViewer::GraphicsWindowWin32* Win32WindowingSystem::getGraphicsWindowFor( HWND
 //////////////////////////////////////////////////////////////////////////////
 
 GraphicsWindowWin32::GraphicsWindowWin32( osg::GraphicsContext::Traits* traits )
-: _hwnd(0),
-  _hdc(0),
-  _hglrc(0),
-  _currentCursor(0),
+: _currentCursor(0),
   _windowProcedure(0),
   _timeOfLastCheckEvents(-1.0),
   _screenOriginX(0),
@@ -1783,8 +1780,8 @@ bool GraphicsWindowWin32::realizeImplementation()
         
         if (_traits.valid() && _traits->sharedContext)
         {
-            GraphicsWindowWin32* sharedContextWin32 = dynamic_cast<GraphicsWindowWin32*>(_traits->sharedContext);
-            if (sharedContextWin32)
+            GraphicsHandleWin32* graphicsHandleWin32 = dynamic_cast<GraphicsHandleWin32*>(_traits->sharedContext);
+            if (graphicsHandleWin32)
             {
                 struct RestoreContext
                 {
@@ -1804,7 +1801,7 @@ bool GraphicsWindowWin32::realizeImplementation()
                     HDC        _hdc;
                     HGLRC    _hglrc;
                 } restoreContext;
-
+                
                 _realized = true;
                 bool result = makeCurrent();
                 _realized = false;
@@ -1813,7 +1810,7 @@ bool GraphicsWindowWin32::realizeImplementation()
                 {
                     return false;        
                 }
-                if (!wglShareLists(sharedContextWin32->getWGLContext(), getWGLContext()))
+                if (!wglShareLists(graphicsHandleWin32->getWGLContext(), getWGLContext()))
                 {
                     reportErrorForScreen("GraphicsWindowWin32::realizeImplementation() - Unable to share OpenGL context", _traits->screenNum, ::GetLastError());
                     return false;
diff --git a/src/osgViewer/GraphicsWindowX11.cpp b/src/osgViewer/GraphicsWindowX11.cpp
index 4e7aebec5..7e5bed95a 100644
--- a/src/osgViewer/GraphicsWindowX11.cpp
+++ b/src/osgViewer/GraphicsWindowX11.cpp
@@ -693,22 +693,9 @@ void GraphicsWindowX11::init()
         }    
     }
 
-    Context sharedContextGLX = NULL;
-
-    // get any shared GLX contexts    
-    GraphicsWindowX11* graphicsWindowX11 = dynamic_cast<GraphicsWindowX11*>(_traits->sharedContext);
-    if (graphicsWindowX11) 
-    {
-        sharedContextGLX = graphicsWindowX11->getContext();
-    }
-    else
-    {
-        PixelBufferX11* pixelBufferX11 = dynamic_cast<PixelBufferX11*>(_traits->sharedContext);
-        if (pixelBufferX11 && pixelBufferX11->valid())
-        {
-            sharedContextGLX = pixelBufferX11->getContext();
-        }
-    }
+    // get any shared GLX contexts
+    GraphicsHandleX11* graphicsHandleX11 = dynamic_cast<GraphicsHandleX11*>(_traits->sharedContext);
+    Context sharedContext = graphicsHandleX11 ? graphicsHandleX11->getContext() : 0;
 
     #ifdef OSG_USE_EGL
 
@@ -774,7 +761,7 @@ void GraphicsWindowX11::init()
             };
         #endif
 
-        _context = eglCreateContext(_eglDisplay, eglConfig, NULL, contextAttribs);
+        _context = eglCreateContext(_eglDisplay, eglConfig, sharedContext, contextAttribs);
         if (_context == EGL_NO_CONTEXT)
         {
             osg::notify(osg::NOTICE)<<"GraphicsWindowX11::init() - eglCreateContext(..) failed."<<std::endl;
@@ -790,7 +777,7 @@ void GraphicsWindowX11::init()
 
     #else
         
-        _context = glXCreateContext( _display, _visualInfo, sharedContextGLX, True );
+        _context = glXCreateContext( _display, _visualInfo, sharedContext, True );
     
         if (!_context)
         {
@@ -989,7 +976,6 @@ bool GraphicsWindowX11::makeCurrentImplementation()
     #ifdef OSG_USE_EGL
         bool result = eglMakeCurrent(_eglDisplay, _eglSurface, _eglSurface, _context)==EGL_TRUE;
         checkEGLError("after eglMakeCurrent()");
-
         return result;
     #else
         return glXMakeCurrent( _display, _window, _context )==True;
@@ -1005,8 +991,9 @@ bool GraphicsWindowX11::releaseContextImplementation()
     }
 
     #ifdef OSG_USE_EGL
-        return eglMakeCurrent( _eglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT )==EGL_TRUE;
+        bool result = eglMakeCurrent( _eglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT )==EGL_TRUE;
         checkEGLError("after eglMakeCurrent() release");
+        return result;
     #else
         return glXMakeCurrent( _display, None, NULL )==True;
     #endif
diff --git a/src/osgViewer/PixelBufferCarbon.cpp b/src/osgViewer/PixelBufferCarbon.cpp
index b2f7c2684..c995c3933 100644
--- a/src/osgViewer/PixelBufferCarbon.cpp
+++ b/src/osgViewer/PixelBufferCarbon.cpp
@@ -80,19 +80,11 @@ bool PixelBufferCarbon::realizeImplementation()
     
     AGLContext sharedContext = NULL;
 
-    // get any shared GLX contexts    
-    GraphicsWindowCarbon* graphicsWindowCarbon = dynamic_cast<GraphicsWindowCarbon*>(_traits->sharedContext);
-    if (graphicsWindowCarbon) 
+    // get any shared AGL contexts    
+    GraphicsHandleCarbon* graphicsHandleCarbon = dynamic_cast<GraphicsHandleCarbon*>(_traits->sharedContext);
+    if (graphicsHandleCarbon) 
     {
-        sharedContext = graphicsWindowCarbon->getAGLContext();
-    }
-    else
-    {
-        PixelBufferCarbon* pixelBufferCarbon = dynamic_cast<PixelBufferCarbon*>(_traits->sharedContext);
-        if (pixelBufferCarbon)
-        {
-            sharedContext = pixelBufferCarbon->getAGLContext();
-        }
+        sharedContext = graphicsHandleCarbon->getAGLContext();
     }
     
     _context = aglCreateContext (_pixelformat, sharedContext);
diff --git a/src/osgViewer/PixelBufferWin32.cpp b/src/osgViewer/PixelBufferWin32.cpp
index e323a6086..3013dc672 100644
--- a/src/osgViewer/PixelBufferWin32.cpp
+++ b/src/osgViewer/PixelBufferWin32.cpp
@@ -445,9 +445,6 @@ using namespace osgViewer;
 
 
 PixelBufferWin32::PixelBufferWin32( osg::GraphicsContext::Traits* traits ):
-  _hwnd(0),
-  _hdc(0),
-  _hglrc(0),
   _initialized(false),
   _valid(false),
   _realized(false),
@@ -657,27 +654,15 @@ bool PixelBufferWin32::realizeImplementation()
 
     makeCurrentImplementation();
 
-    if (_traits->sharedContext)
+    if ( _traits->sharedContext )
     {
-        HGLRC hglrc = 0;
-
-        GraphicsWindowWin32* graphicsWindowWin32 = dynamic_cast<GraphicsWindowWin32*>(_traits->sharedContext);
-        if (graphicsWindowWin32) 
+        GraphicsHandleWin32* graphicsHandleWin32 = dynamic_cast<GraphicsHandleWin32*>(_traits->sharedContext);
+        if (graphicsHandleWin32) 
         {
-            hglrc = graphicsWindowWin32->getWGLContext();
-        }
-        else
-        {
-            PixelBufferWin32* pixelBufferWin32 = dynamic_cast<PixelBufferWin32*>(_traits->sharedContext);
-            if (pixelBufferWin32)
+            if ( !wglShareLists(graphicsHandleWin32->getWGLContext(), _hglrc) )
             {
-                hglrc = pixelBufferWin32->getWGLContext();
-            }
-        }
-
-        if ( !wglShareLists(hglrc, _hglrc) )
-        {
             osg::notify(osg::NOTICE) << "PixelBufferWin32::realizeImplementation, wglShareLists error: " << sysError() << std::endl;
+            }
         }
     }
 
@@ -757,15 +742,10 @@ bool PixelBufferWin32::makeContextCurrentImplementation( GraphicsContext* readCo
         return false;
     }
 
-    GraphicsWindowWin32* graphicsWindowWin32 = dynamic_cast<GraphicsWindowWin32*>(readContext);
-    if (graphicsWindowWin32) 
+    GraphicsHandleWin32* graphicsHandleWin32 = dynamic_cast<GraphicsHandleWin32*>(readContext);
+    if (graphicsHandleWin32) 
     {
-        return wgle->wglMakeContextCurrentARB(_hdc, graphicsWindowWin32->getHDC(), _hglrc);
-    }
-    PixelBufferWin32* pixelBufferWin32 = dynamic_cast<PixelBufferWin32*>(_traits->sharedContext);
-    if (pixelBufferWin32)
-    {
-        return wgle->wglMakeContextCurrentARB(_hdc, pixelBufferWin32->getHDC(), _hglrc);
+        return wgle->wglMakeContextCurrentARB(_hdc, graphicsHandleWin32->getHDC(), _hglrc);
     }
     return false;
 }
diff --git a/src/osgViewer/PixelBufferX11.cpp b/src/osgViewer/PixelBufferX11.cpp
index 23b252e2b..fee2e3590 100644
--- a/src/osgViewer/PixelBufferX11.cpp
+++ b/src/osgViewer/PixelBufferX11.cpp
@@ -28,10 +28,8 @@ using namespace osgViewer;
 
 PixelBufferX11::PixelBufferX11(osg::GraphicsContext::Traits* traits)
   : _valid(false),
-    _display(0),
     _pbuffer(0),
     _visualInfo(0),
-    _context(0),
     _initialized(false),
     _realized(false),
     _useGLX1_3(false)
@@ -217,24 +215,11 @@ void PixelBufferX11::init()
         }    
     }
     
-    GLXContext sharedContextGLX = NULL;
+    // get any shared GLX contexts
+    GraphicsHandleX11* graphicsHandleX11 = dynamic_cast<GraphicsHandleX11*>(_traits->sharedContext);
+    Context sharedContext = graphicsHandleX11 ? graphicsHandleX11->getContext() : 0;
 
-    // get any shared GLX contexts    
-    GraphicsWindowX11* graphicsWindowX11 = dynamic_cast<GraphicsWindowX11*>(_traits->sharedContext);
-    if (graphicsWindowX11) 
-    {
-        sharedContextGLX = graphicsWindowX11->getContext();
-    }
-    else
-    {
-        PixelBufferX11* pixelBufferX11 = dynamic_cast<PixelBufferX11*>(_traits->sharedContext);
-        if (pixelBufferX11)
-        {
-            sharedContextGLX = pixelBufferX11->getContext();
-        }
-    }
-    
-    _context = glXCreateContext( _display, _visualInfo, sharedContextGLX, True );
+    _context = glXCreateContext( _display, _visualInfo, sharedContext, True );
 
     if (!_context)
     {
diff --git a/src/osgViewer/ScreenCaptureHandler.cpp b/src/osgViewer/ScreenCaptureHandler.cpp
index c4186de74..41c95b62c 100644
--- a/src/osgViewer/ScreenCaptureHandler.cpp
+++ b/src/osgViewer/ScreenCaptureHandler.cpp
@@ -490,7 +490,9 @@ void WindowCaptureCallback::setCaptureOperation(ScreenCaptureHandler::CaptureOpe
 
 void WindowCaptureCallback::operator () (osg::RenderInfo& renderInfo) const
 {
+#if !defined(OSG_GLES1_AVAILABLE) && !defined(OSG_GLES2_AVAILABLE)
     glReadBuffer(_readBuffer);
+#endif
 
     osg::GraphicsContext* gc = renderInfo.getState()->getGraphicsContext();
     osg::ref_ptr<ContextData> cd = getContextData(gc);