diff --git a/include/osgViewer/GraphicsWindowCarbon b/include/osgViewer/GraphicsWindowCarbon
index 207a6ebdb..81cbae150 100644
--- a/include/osgViewer/GraphicsWindowCarbon
+++ b/include/osgViewer/GraphicsWindowCarbon
@@ -43,8 +43,17 @@ class GraphicsWindowCarbon : public osgViewer::GraphicsWindow
             if (valid())
             {
                 setState( new osg::State );
-                getState()->setContextID( osg::GraphicsContext::createNewContextID() );
                 getState()->setGraphicsContext(this);
+
+                if (_traits.valid() && _traits->sharedContext)
+                {
+                    getState()->setContextID( _traits->sharedContext->getState()->getContextID() );
+                    incrementContextIDUsageCount( getState()->getContextID() );   
+                }
+                else
+                {
+                    getState()->setContextID( osg::GraphicsContext::createNewContextID() );
+                }
             }
         }
     
@@ -95,6 +104,7 @@ class GraphicsWindowCarbon : public osgViewer::GraphicsWindow
         
         void transformMouseXY(float& x, float& y);
         
+        AGLContext& getAGLContext() { return _context; }
 
         bool            _valid;
         bool            _initialized;
diff --git a/include/osgViewer/GraphicsWindowWin32 b/include/osgViewer/GraphicsWindowWin32
index ca60a200a..6688256b3 100644
--- a/include/osgViewer/GraphicsWindowWin32
+++ b/include/osgViewer/GraphicsWindowWin32
@@ -98,6 +98,8 @@ class GraphicsWindowWin32 : public osgViewer::GraphicsWindow
         
         int getScreenNumberContainingWindow( int& _screenOriginX, int& _screenOriginY );
         
+        HGLRC&          getWGLContext() { return _hglrc; }
+        
         HWND            _hwnd;
         HDC             _hdc;
         HGLRC           _hglrc;
diff --git a/include/osgViewer/GraphicsWindowX11 b/include/osgViewer/GraphicsWindowX11
index 43bb84e2a..b0097dcb3 100644
--- a/include/osgViewer/GraphicsWindowX11
+++ b/include/osgViewer/GraphicsWindowX11
@@ -116,7 +116,7 @@ class GraphicsWindowX11 : public osgViewer::GraphicsWindow
         Display* getEventDisplay() { return _eventDisplay; }
         Window& getParent() { return _parent; }
         Window& getWindow() { return _window; }
-        GLXContext getGLXContext() { return _glxContext; }
+        GLXContext& getGLXContext() { return _glxContext; }
 
         Cursor& getDefaultCursor() { return _defaultCursor; }
         Cursor& getNullCursor() { return _nullCursor; }
diff --git a/src/osgViewer/GraphicsWindowCarbon.cpp b/src/osgViewer/GraphicsWindowCarbon.cpp
index 04b3f1afb..88501eebf 100644
--- a/src/osgViewer/GraphicsWindowCarbon.cpp
+++ b/src/osgViewer/GraphicsWindowCarbon.cpp
@@ -259,7 +259,9 @@ class GraphicsContextCarbon : public osg::GraphicsContext
                 osg::notify(osg::WARN) << "GraphicsContext::realizeImplementation() aglChoosePixelFormat failed! " << aglErrorString(aglGetError()) << std::endl;
                 return false;
             }
+            
             _context = aglCreateContext (pixelformat, NULL);
+            
             if (!_context) {
                 osg::notify(osg::WARN) << "GraphicsContext::realizeImplementation() aglCreateContext failed! " << aglErrorString(aglGetError()) << std::endl;
                 return false;
@@ -621,7 +623,17 @@ bool GraphicsWindowCarbon::realizeImplementation()
     }
     
     // create the context
-    _context = aglCreateContext (_pixelFormat, NULL);
+    GraphicsWindowCarbon* sharedContextCarbon = dynamic_cast<GraphicsWindowCarbon*>(_traits->sharedContext);
+    if (sharedContextCarbon) 
+    {
+        _context = aglCreateContext (_pixelFormat, sharedContextCarbon->getAGLContext());
+    }
+    else
+    {
+        _context = aglCreateContext (_pixelFormat, NULL);
+    }
+
+
     if (!_context) {
         osg::notify(osg::WARN) << "GraphicsWindowCarbon::realizeImplementation failed creating a context: " << aglGetError() << std::endl;
         return false;
diff --git a/src/osgViewer/GraphicsWindowWin32.cpp b/src/osgViewer/GraphicsWindowWin32.cpp
index fd7e2736d..4a60558ed 100644
--- a/src/osgViewer/GraphicsWindowWin32.cpp
+++ b/src/osgViewer/GraphicsWindowWin32.cpp
@@ -1005,8 +1005,17 @@ GraphicsWindowWin32::GraphicsWindowWin32( osg::GraphicsContext::Traits* traits )
     if (valid())
     {
         setState( new osg::State );
-        getState()->setContextID( osg::GraphicsContext::createNewContextID() );
         getState()->setGraphicsContext(this);
+
+        if (_traits.valid() && _traits->sharedContext)
+        {
+            getState()->setContextID( _traits->sharedContext->getState()->getContextID() );
+            incrementContextIDUsageCount( getState()->getContextID() );   
+        }
+        else
+        {
+            getState()->setContextID( osg::GraphicsContext::createNewContextID() );
+        }
     }
 }
 
@@ -1401,6 +1410,16 @@ bool GraphicsWindowWin32::realizeImplementation()
     {
         init();
         if (!_initialized) return false;
+        
+        if (_traits.valid && _traits->sharedContext)
+        {
+            GraphicsWindowWin32* sharedContextWin32 = dynamic_cast<GraphicsWindowWin32*>(_traits->sharedContext);
+            if (sharedContextWin32)
+            {
+                makeCurrent();        
+                wglShareLists( sharedContextWin32->getWGLContext(), getWGLContext() );
+            }
+        }
     }
 
     //
diff --git a/src/osgViewer/GraphicsWindowX11.cpp b/src/osgViewer/GraphicsWindowX11.cpp
index 74ad30128..3d15a6130 100644
--- a/src/osgViewer/GraphicsWindowX11.cpp
+++ b/src/osgViewer/GraphicsWindowX11.cpp
@@ -422,13 +422,16 @@ void GraphicsWindowX11::init()
         }    
     }
     
-    // need to pick up from traits
-    GLXContext sharedGLContext = 0;
     
     GraphicsWindowX11* sharedContextX11 = dynamic_cast<GraphicsWindowX11*>(_traits->sharedContext);
-    if (sharedContextX11) sharedGLContext = sharedContextX11->getGLXContext();
-    
-    _glxContext = glXCreateContext( _display, _visualInfo, sharedGLContext, True );
+    if (sharedContextX11) 
+    {
+        _glxContext = glXCreateContext( _display, _visualInfo, sharedContextX11->getGLXContext(), True );
+    }
+    else
+    {
+        _glxContext = glXCreateContext( _display, _visualInfo, NULL, True );
+    }
     
     if (!_glxContext)
     {