diff --git a/src/osgGA/StateSetManipulator.cpp b/src/osgGA/StateSetManipulator.cpp
index a4be13f7b..8fcd70209 100644
--- a/src/osgGA/StateSetManipulator.cpp
+++ b/src/osgGA/StateSetManipulator.cpp
@@ -56,6 +56,35 @@ const StateSet *StateSetManipulator::getStateSet() const
     return _stateset.get();
 }
 
+void StateSetManipulator::clone()
+{
+    if (!_stateset) return;
+    
+    // we clone the StateSet so that any draw traversals that might be running at the time of the
+    // event traversal won't change the same StateSet that is being read.  One could just set the 
+    // DataVariance to DYNAMIC to avoid this overlap, but this would introduce a performance penalty.
+    
+    StateSet::ParentList parents = _stateset->getParents();
+    osg::ref_ptr<osg::StateSet> newStateSet = dynamic_cast<osg::StateSet*>(_stateset->clone(osg::CopyOp::SHALLOW_COPY));
+
+    // change the parents of the original StateSet to point to the new stateset
+    for(StateSet::ParentList::iterator itr = parents.begin();
+        itr !=  parents.end();
+        ++itr)
+    {
+        osg::Object* object = *itr;
+        osg::Node* node = dynamic_cast<osg::Node*>(object);
+        if (node) node->setStateSet(newStateSet.get());
+        else
+        {
+            osg::Drawable* drawable = dynamic_cast<osg::Drawable*>(object);
+            if (drawable) drawable->setStateSet(newStateSet.get());
+        }
+    }
+    
+    _stateset = newStateSet;
+}
+
 bool StateSetManipulator::handle(const GUIEventAdapter& ea,GUIActionAdapter& aa)
 {
     if(!_stateset.valid()) return false;
@@ -119,6 +148,10 @@ void StateSetManipulator::getUsage(osg::ApplicationUsage& usage) const
 
 void StateSetManipulator::setBackfaceEnabled(bool newbackface)
 {
+    if (_backface == newbackface) return;
+    
+    clone();
+    
     _backface = newbackface;
     if( _backface ) _stateset->setMode(GL_CULL_FACE,osg::StateAttribute::ON);
     else _stateset->setMode(GL_CULL_FACE,osg::StateAttribute::OVERRIDE|osg::StateAttribute::OFF);
@@ -126,6 +159,10 @@ void StateSetManipulator::setBackfaceEnabled(bool newbackface)
 
 void StateSetManipulator::setLightingEnabled(bool newlighting)
 {
+    if (_lighting == newlighting) return;
+    
+    clone();
+
     _lighting = newlighting;
     if( _lighting ) _stateset->setMode(GL_LIGHTING,osg::StateAttribute::ON);
     else _stateset->setMode(GL_LIGHTING,osg::StateAttribute::OVERRIDE|osg::StateAttribute::OFF);
@@ -133,6 +170,10 @@ void StateSetManipulator::setLightingEnabled(bool newlighting)
 
 void StateSetManipulator::setTextureEnabled(bool newtexture)
 {
+    if (_texture==newtexture) return;
+    
+    clone();
+
     _texture = newtexture;
 //    osg::ref_ptr< osg::Texture > tex = dynamic_cast<osg::Texture*>
 //        ( _stateset->getAttribute( osg::StateAttribute::TEXTURE ) );
@@ -152,6 +193,8 @@ void StateSetManipulator::setTextureEnabled(bool newtexture)
 
 void StateSetManipulator::setPolygonMode(osg::PolygonMode::Mode newpolygonmode)
 {
+    clone();
+
     osg::PolygonMode* polyModeObj = getOrCreatePolygonMode();
 
     polyModeObj->setMode(osg::PolygonMode::FRONT_AND_BACK,newpolygonmode);
@@ -159,6 +202,8 @@ void StateSetManipulator::setPolygonMode(osg::PolygonMode::Mode newpolygonmode)
 
 void StateSetManipulator::cyclePolygonMode()
 {
+    clone();
+
     osg::PolygonMode* polyModeObj = getOrCreatePolygonMode();
 
     osg::PolygonMode::Mode currentMode = getPolygonMode();