diff --git a/include/osgViewer/api/X11/PixelBufferX11 b/include/osgViewer/api/X11/PixelBufferX11
index e4555a674..9e815f8a3 100644
--- a/include/osgViewer/api/X11/PixelBufferX11
+++ b/include/osgViewer/api/X11/PixelBufferX11
@@ -83,6 +83,17 @@ class OSGVIEWER_EXPORT PixelBufferX11 : public osg::GraphicsContext, public osgV
         bool            _realized;
 
         bool            _useGLX1_3;
+        bool            _useSGIX;
+
+        typedef Pbuffer ( *GLXCreateGLXPbufferSGIX_FuncPtr) (Display *dpy, GLXFBConfig config, unsigned int, unsigned height, int* attrib_list);
+        typedef void ( *GLXDestroyGLXPbufferSGIX_FuncPtr) (Display *dpy, Pbuffer pbuf);
+        typedef int ( *GLXQueryGLXPbufferSGIX_FuncCPtr) (Display *dpy, Pbuffer pbuf, int attribute, unsigned int *value);
+        typedef GLXFBConfig ( *GLXGetFBConfigFromVisualSGIX_FuncPtr) (Display *dpy, XVisualInfo *vis);
+
+        GLXCreateGLXPbufferSGIX_FuncPtr _glXCreateGLXPbufferSGIX;
+        GLXDestroyGLXPbufferSGIX_FuncPtr _glXDestroyGLXPbufferSGIX;
+        GLXQueryGLXPbufferSGIX_FuncCPtr _glXQueryGLXPbufferSGIX;
+        GLXGetFBConfigFromVisualSGIX_FuncPtr _glXGetFBConfigFromVisualSGIX;
 };
 
 }
diff --git a/src/osgViewer/PixelBufferX11.cpp b/src/osgViewer/PixelBufferX11.cpp
index c835828db..8661af14e 100644
--- a/src/osgViewer/PixelBufferX11.cpp
+++ b/src/osgViewer/PixelBufferX11.cpp
@@ -32,7 +32,12 @@ PixelBufferX11::PixelBufferX11(osg::GraphicsContext::Traits* traits)
     _visualInfo(0),
     _initialized(false),
     _realized(false),
-    _useGLX1_3(false)
+    _useGLX1_3(false),
+    _useSGIX(false),
+    _glXCreateGLXPbufferSGIX(NULL),
+    _glXDestroyGLXPbufferSGIX(NULL),
+    _glXQueryGLXPbufferSGIX(NULL),
+    _glXGetFBConfigFromVisualSGIX(NULL)
 {
     _traits = traits;
 
@@ -181,6 +186,20 @@ void PixelBufferX11::init()
         const char *extensions = glXQueryExtensionsString(_display, screen);
         haveSGIX_pbuffer = osg::isExtensionInExtensionString("GLX_SGIX_pbuffer", extensions)
            && osg::isExtensionInExtensionString("GLX_SGIX_fbconfig", extensions);
+
+        if (haveSGIX_pbuffer)
+        {
+            osg::setGLExtensionFuncPtr(_glXCreateGLXPbufferSGIX, "glXDestroyGLXPbufferSGIX");
+            osg::setGLExtensionFuncPtr(_glXDestroyGLXPbufferSGIX, "glXDestroyGLXPbufferSGIX");
+            osg::setGLExtensionFuncPtr(_glXQueryGLXPbufferSGIX, "glXDestroyGLXPbufferSGIX");
+            osg::setGLExtensionFuncPtr(_glXGetFBConfigFromVisualSGIX, "glXGetFBConfigFromVisualSGIX");
+            if (_glXCreateGLXPbufferSGIX == NULL ||
+                _glXDestroyGLXPbufferSGIX == NULL ||
+                _glXQueryGLXPbufferSGIX == NULL ||
+                _glXGetFBConfigFromVisualSGIX == NULL) {
+                haveSGIX_pbuffer = false;
+            }
+        }
     }
 #endif
 
@@ -283,7 +302,7 @@ void PixelBufferX11::init()
     // If we still have no pbuffer but a capable display with the SGIX extension, try to use that
     if (!_pbuffer && haveSGIX_pbuffer)
     {
-        GLXFBConfigSGIX fbconfig = glXGetFBConfigFromVisualSGIX( _display, _visualInfo );
+        GLXFBConfigSGIX fbconfig = _glXGetFBConfigFromVisualSGIX( _display, _visualInfo );
         typedef std::vector <int> AttributeList;
 
         AttributeList attributes;
@@ -291,14 +310,15 @@ void PixelBufferX11::init()
         attributes.push_back( GL_TRUE );
         attributes.push_back( 0L );
 
-        _pbuffer = glXCreateGLXPbufferSGIX(_display, fbconfig, _traits->width, _traits->height,  &attributes.front() );
+        _pbuffer = _glXCreateGLXPbufferSGIX(_display, fbconfig, _traits->width, _traits->height,  &attributes.front() );
         if (_pbuffer)
         {
+            _useSGIX = true;
             int iWidth = 0;
             int iHeight = 0;
-            glXQueryGLXPbufferSGIX(_display, _pbuffer, GLX_WIDTH_SGIX , (unsigned int *)&iWidth);
-            glXQueryGLXPbufferSGIX(_display, _pbuffer, GLX_HEIGHT_SGIX, (unsigned int *)&iHeight);
-
+            _glXQueryGLXPbufferSGIX(_display, _pbuffer, GLX_WIDTH_SGIX , (unsigned int *)&iWidth);
+            _glXQueryGLXPbufferSGIX(_display, _pbuffer, GLX_HEIGHT_SGIX, (unsigned int *)&iHeight);
+                                                                                        
             if (_traits->width != iWidth || _traits->height != iHeight)
             {
                 OSG_NOTICE << "PixelBufferX11::init(), SGIX_pbuffer created with different size then requsted" << std::endl;
@@ -351,7 +371,10 @@ void PixelBufferX11::closeImplementation()
             else
             {
 #ifdef GLX_SGIX_pbuffer
-                glXDestroyGLXPbufferSGIX(_display, _pbuffer);
+                if (_useSGIX)
+                {
+                    _glXDestroyGLXPbufferSGIX(_display, _pbuffer);
+                }
 #endif
             }
         }