diff --git a/include/osg/DisplaySettings b/include/osg/DisplaySettings
index 52f81172d..4ab5bd18d 100644
--- a/include/osg/DisplaySettings
+++ b/include/osg/DisplaySettings
@@ -19,6 +19,10 @@ class SG_EXPORT DisplaySettings : public osg::Referenced
 
     public:
 
+        /** Maintain a DisplaySettings singleton for objects to querry at runtime.*/
+        static DisplaySettings* instance();
+
+
         DisplaySettings()
         {
             setDefaults();
@@ -36,7 +40,10 @@ class SG_EXPORT DisplaySettings : public osg::Referenced
         
         virtual ~DisplaySettings();
 
+        
+
         DisplaySettings& operator = (const DisplaySettings& vs);
+ 
         
         void merge(const DisplaySettings& vs);
 
@@ -95,6 +102,11 @@ class SG_EXPORT DisplaySettings : public osg::Referenced
         const unsigned int getMinimumNumStencilBits() const { return _minimumNumberStencilBits; }
         const bool getStencilBuffer() const { return _minimumNumberStencilBits!=0; }
 
+
+        void setMaxNumberOfGraphicsContexts(const int num) { _maxNumOfGraphicsContexts = num; }
+        const int getMaxNumberOfGraphicsContexts() const { return _maxNumOfGraphicsContexts; }
+
+
     protected:
     
         void copy(const DisplaySettings& vs);
@@ -111,6 +123,7 @@ class SG_EXPORT DisplaySettings : public osg::Referenced
         unsigned int    _minimumNumberAlphaBits;
         unsigned int    _minimumNumberStencilBits;
 
+        int             _maxNumOfGraphicsContexts;
 
 };
 
diff --git a/include/osg/Texture b/include/osg/Texture
index 364f66d3d..d4d4dc727 100644
--- a/include/osg/Texture
+++ b/include/osg/Texture
@@ -248,13 +248,23 @@ class SG_EXPORT Texture : public StateAttribute
         inline GLuint& getHandle(const uint contextID) const
         {
             // pad out handle list if required.
-            while (_handleList.size()<=contextID)
-                _handleList.push_back(0);
+            if (_handleList.size()<=contextID)
+                _handleList.resize(contextID,0);
 
             // get the globj for the current contextID.
             return _handleList[contextID];
         }
 
+        inline uint& getModifiedTag(const uint contextID) const
+        {
+            // pad out handle list if required.
+            if (_modifiedTag.size()<=contextID)
+                _modifiedTag.resize(contextID,0);
+
+            // get the modified tag for the current contextID.
+            return _modifiedTag[contextID];
+        }
+
         /** Force a recompile on next apply() of associated OpenGL texture objects.*/
         void dirtyTextureObject();
 
diff --git a/include/osg/Transform b/include/osg/Transform
index 270fa2fcd..9d896cbb1 100644
--- a/include/osg/Transform
+++ b/include/osg/Transform
@@ -120,16 +120,16 @@ class SG_EXPORT Transform : public Group
         
 
         /** Set the transform's matrix.*/
-        void setMatrix(const Matrix& mat) { (*_matrix) = mat; _inverseDirty=true; dirtyBound(); }
+        void setMatrix(const Matrix& mat) { (*_matrix) = mat; _inverseDirty=true; computeInverse(); dirtyBound(); }
         
         /** Get the transform's matrix. */
         inline const Matrix& getMatrix() const { return *_matrix; }
 
         /** preMult transform.*/
-        void preMult(const Matrix& mat) { _matrix->preMult(mat); _inverseDirty=true; dirtyBound(); }
+        void preMult(const Matrix& mat) { _matrix->preMult(mat); _inverseDirty=true; computeInverse(); dirtyBound(); }
         
         /** postMult transform.*/
-        void postMult(const Matrix& mat)  { _matrix->postMult(mat); _inverseDirty=true; dirtyBound(); }
+        void postMult(const Matrix& mat)  { _matrix->postMult(mat); _inverseDirty=true; computeInverse(); dirtyBound(); }
     
 
     protected :
diff --git a/include/osgDB/Registry b/include/osgDB/Registry
index c5567cc5b..1ed528525 100644
--- a/include/osgDB/Registry
+++ b/include/osgDB/Registry
@@ -34,10 +34,10 @@ class OSGDB_EXPORT Registry
 {
     public:
 
-        ~Registry();
-
         static Registry* instance();
 
+        ~Registry();
+
 
         /** read the command line string list, removing any matched control sequences.*/
         void readCommandLine(std::vector<std::string>& commandLine);
diff --git a/src/osg/DisplaySettings.cpp b/src/osg/DisplaySettings.cpp
index 37546907e..05854eb1c 100644
--- a/src/osg/DisplaySettings.cpp
+++ b/src/osg/DisplaySettings.cpp
@@ -3,9 +3,28 @@
 #include <algorithm>
 
 using namespace osg;
-
 using namespace std;
 
+class DisplaySettingsPtr
+{
+    public:
+        DisplaySettingsPtr() : _ptr(0L) {}
+        DisplaySettingsPtr(DisplaySettings* t): _ptr(t) {}
+        DisplaySettingsPtr(const DisplaySettingsPtr& rp):_ptr(rp._ptr) { }
+        ~DisplaySettingsPtr() { if (_ptr) delete _ptr; _ptr=0L; }
+
+        inline DisplaySettings* get() { return _ptr; }
+
+        DisplaySettings* _ptr;
+};
+
+DisplaySettings* DisplaySettings::instance()
+{
+    static DisplaySettingsPtr s_displaySettings = new DisplaySettings;
+    return s_displaySettings.get();
+}
+
+
 DisplaySettings::DisplaySettings(const DisplaySettings& vs):Referenced()
 {
     copy(vs);
@@ -15,7 +34,8 @@ DisplaySettings::~DisplaySettings()
 {
 }
 
-DisplaySettings& DisplaySettings::operator = (const DisplaySettings& vs)
+ 
+ DisplaySettings& DisplaySettings::operator = (const DisplaySettings& vs)
 {
     if (this==&vs) return *this;
     copy(vs);
@@ -34,6 +54,8 @@ void DisplaySettings::copy(const DisplaySettings& vs)
     _depthBuffer = vs._depthBuffer;
     _minimumNumberAlphaBits = vs._minimumNumberAlphaBits;
     _minimumNumberStencilBits = vs._minimumNumberStencilBits;
+
+    _maxNumOfGraphicsContexts = vs._maxNumOfGraphicsContexts;
 }
 
 void DisplaySettings::merge(const DisplaySettings& vs)
@@ -63,6 +85,12 @@ void DisplaySettings::setDefaults()
     _depthBuffer = true;
     _minimumNumberAlphaBits = 0;
     _minimumNumberStencilBits = 0;
+    
+    #ifdef __sgi
+    _maxNumOfGraphicsContexts = 4;
+    #else
+    _maxNumOfGraphicsContexts = 1;
+    #endif
 }
 
 void DisplaySettings::readEnvironmentalVariables()
@@ -118,6 +146,11 @@ void DisplaySettings::readEnvironmentalVariables()
     {
         _screenHeight = atof(ptr);
     }
+
+    if( (ptr = getenv("OSG_MAX_NUMBER_OF_GRAPHICS_CONTEXTS")) != 0)
+    {
+        _maxNumOfGraphicsContexts = atof(ptr);
+    }
 }
 
 void DisplaySettings::readCommandLine(std::vector<std::string>& commandLine)
diff --git a/src/osg/Drawable.cpp b/src/osg/Drawable.cpp
index dcdfdee06..bae04228b 100644
--- a/src/osg/Drawable.cpp
+++ b/src/osg/Drawable.cpp
@@ -15,6 +15,8 @@ Drawable::DeletedDisplayListCache Drawable::s_deletedDisplayListCache;
 
 Drawable::Drawable()
 {
+    _globjList.resize(DisplaySettings::instance()->getMaxNumberOfGraphicsContexts(),0);
+
     _bbox_computed = false;
 
     // Note, if your are defining a subclass from drawable which is
diff --git a/src/osg/Texture.cpp b/src/osg/Texture.cpp
index b1ea15925..ae734a447 100644
--- a/src/osg/Texture.cpp
+++ b/src/osg/Texture.cpp
@@ -18,6 +18,9 @@ Texture::DeletedTextureObjectCache Texture::s_deletedTextureObjectCache;
 
 Texture::Texture()
 {
+    _handleList.resize(DisplaySettings::instance()->getMaxNumberOfGraphicsContexts(),0);
+    _modifiedTag.resize(DisplaySettings::instance()->getMaxNumberOfGraphicsContexts(),0);
+
     _textureUnit = 0;
 
     _wrap_s    = CLAMP;
@@ -189,12 +192,10 @@ void Texture::apply(State& state) const
         }
         else  if (_image.valid() && _image->data())
         {
-            // pad out the modified tag list, if required.
-            while (_modifiedTag.size() <= contextID)
-                _modifiedTag.push_back(0);
+            uint& modifiedTag = getModifiedTag(contextID);
 
             if (_subloadMode == AUTO ||
-                (_subloadMode == IF_DIRTY && _modifiedTag[contextID] != _image->getModifiedTag()))
+                (_subloadMode == IF_DIRTY && modifiedTag != _image->getModifiedTag()))
             {
                 glBindTexture( GL_TEXTURE_2D, handle );
                 glTexSubImage2D(GL_TEXTURE_2D, 0,
@@ -203,7 +204,7 @@ void Texture::apply(State& state) const
                                 (GLenum) _image->pixelFormat(), (GLenum) _image->dataType(),
                                 _image->data());
                 // update the modified flag to show that the image has been loaded.
-                _modifiedTag[contextID] = _image->getModifiedTag();
+                modifiedTag = _image->getModifiedTag();
             }
         }
     }
@@ -240,12 +241,8 @@ void Texture::applyImmediateMode(State& state) const
     // current OpenGL context.
     const uint contextID = state.getContextID();
 
-    // pad out the modified tag list, if required.
-    while (_modifiedTag.size() <= contextID)
-        _modifiedTag.push_back(0);
-
     // update the modified tag to show that it is upto date.
-    _modifiedTag[contextID] = _image->getModifiedTag();
+    getModifiedTag(contextID) = _image->getModifiedTag();
 
 
     if (_subloadMode == OFF)
diff --git a/src/osgDB/Registry.cpp b/src/osgDB/Registry.cpp
index fcd044dac..957f3291b 100644
--- a/src/osgDB/Registry.cpp
+++ b/src/osgDB/Registry.cpp
@@ -32,6 +32,13 @@ class RegistryPtr
         Registry* _ptr;
 };
 
+Registry* Registry::instance()
+{
+    static RegistryPtr s_nodeFactory = new Registry;
+    return s_nodeFactory.get();
+}
+
+
 // definition of the Registry
 Registry::Registry()
 {
@@ -63,11 +70,6 @@ Registry::~Registry()
 }
 
 
-Registry* Registry::instance()
-{
-    static RegistryPtr s_nodeFactory = new Registry;
-    return s_nodeFactory.get();
-}
 
 void Registry::readCommandLine(std::vector<std::string>& commandLine)
 {