diff --git a/Core/Code/Rendering/mitkVtkPropRenderer.cpp b/Core/Code/Rendering/mitkVtkPropRenderer.cpp
index 358f50423a..3e36cad61f 100644
--- a/Core/Code/Rendering/mitkVtkPropRenderer.cpp
+++ b/Core/Code/Rendering/mitkVtkPropRenderer.cpp
@@ -1,999 +1,1005 @@
 /*===================================================================
 
 The Medical Imaging Interaction Toolkit (MITK)
 
 Copyright (c) German Cancer Research Center,
 Division of Medical and Biological Informatics.
 All rights reserved.
 
 This software is distributed WITHOUT ANY WARRANTY; without
 even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.
 
 See LICENSE.txt or http://www.mitk.org for details.
 
 ===================================================================*/
 
 
 #include "mitkVtkPropRenderer.h"
 
 // MAPPERS
 #include "mitkMapper.h"
 #include "mitkImageVtkMapper2D.h"
 #include "mitkVtkMapper.h"
 #include "mitkGLMapper.h"
 #include "mitkGeometry2DDataVtkMapper3D.h"
 
 #include "mitkImageSliceSelector.h"
 #include "mitkRenderingManager.h"
 #include "mitkGL.h"
 #include "mitkGeometry3D.h"
 #include "mitkDisplayGeometry.h"
 #include "mitkLevelWindow.h"
 #include "mitkCameraController.h"
 #include "mitkVtkInteractorCameraController.h"
 #include "mitkPlaneGeometry.h"
 #include "mitkProperties.h"
 #include "mitkSurface.h"
 #include "mitkNodePredicateDataType.h"
 #include "mitkVtkInteractorStyle.h"
 
 // VTK
 #include <vtkRenderer.h>
 #include <vtkRendererCollection.h>
 #include <vtkLight.h>
 #include <vtkLightKit.h>
 #include <vtkRenderWindow.h>
 #include <vtkLinearTransform.h>
 #include <vtkCamera.h>
 #include <vtkWorldPointPicker.h>
 #include <vtkPointPicker.h>
 #include <vtkCellPicker.h>
 #include <vtkTextActor.h>
 #include <vtkTextProperty.h>
 #include <vtkProp.h>
 #include <vtkAssemblyPath.h>
 #include <vtkAssemblyNode.h>
 #include <vtkMapper.h>
 #include <vtkSmartPointer.h>
 #include <vtkTransform.h>
 #include <vtkInteractorStyleTrackballCamera.h>
 
 
 mitk::VtkPropRenderer::VtkPropRenderer( const char* name, vtkRenderWindow * renWin, mitk::RenderingManager* rm )
   : BaseRenderer(name,renWin, rm),
   m_VtkMapperPresent(false),
   m_CameraInitializedForMapperID(0)
 {
   didCount=false;
 
   m_WorldPointPicker = vtkWorldPointPicker::New();
 
   m_PointPicker = vtkPointPicker::New();
   m_PointPicker->SetTolerance( 0.0025 );
 
   m_CellPicker = vtkCellPicker::New();
   m_CellPicker->SetTolerance( 0.0025 );
 
   mitk::Geometry2DDataVtkMapper3D::Pointer geometryMapper = mitk::Geometry2DDataVtkMapper3D::New();
   m_CurrentWorldGeometry2DMapper = geometryMapper;
   m_CurrentWorldGeometry2DNode->SetMapper(2, geometryMapper);
 
   m_LightKit = vtkLightKit::New();
   m_LightKit->AddLightsToRenderer(m_VtkRenderer);
   m_PickingMode = WorldPointPicking;
 
   m_TextRenderer = vtkRenderer::New();
   m_TextRenderer->SetRenderWindow(renWin);
   m_TextRenderer->SetInteractive(0);
   m_TextRenderer->SetErase(0);
 }
 
 /*!
 \brief Destructs the VtkPropRenderer.
 */
 mitk::VtkPropRenderer::~VtkPropRenderer()
 {
   // Workaround for GLDisplayList Bug
   {
     m_MapperID=0;
     checkState();
   }
 
   if (m_LightKit != NULL)
     m_LightKit->Delete();
 
   if (m_VtkRenderer!=NULL)
   {
     m_CameraController = NULL;
 
     m_VtkRenderer->Delete();
 
     m_VtkRenderer = NULL;
   }
   else
     m_CameraController = NULL;
 
   if (m_WorldPointPicker != NULL)
     m_WorldPointPicker->Delete();
   if (m_PointPicker != NULL)
     m_PointPicker->Delete();
   if (m_CellPicker != NULL)
     m_CellPicker->Delete();
   if (m_TextRenderer != NULL)
     m_TextRenderer->Delete();
 }
 
 
 void mitk::VtkPropRenderer::SetDataStorage(  mitk::DataStorage* storage  )
 {
   if ( storage == NULL )
     return;
 
   BaseRenderer::SetDataStorage(storage);
 
   static_cast<mitk::Geometry2DDataVtkMapper3D*>(m_CurrentWorldGeometry2DMapper.GetPointer())->SetDataStorageForTexture( m_DataStorage.GetPointer() );
 
   // Compute the geometry from the current data tree bounds and set it as world geometry
   this->SetWorldGeometryToDataStorageBounds();
 }
 
 
 bool mitk::VtkPropRenderer::SetWorldGeometryToDataStorageBounds()
 {
   if ( m_DataStorage.IsNull() )
     return false;
 
   //initialize world geometry
   mitk::TimeSlicedGeometry::Pointer geometry = m_DataStorage->ComputeVisibleBoundingGeometry3D( NULL, "includeInBoundingBox" );
 
   if ( geometry.IsNull() )
     return false;
 
   this->SetWorldGeometry(geometry);
   //this->GetDisplayGeometry()->SetSizeInDisplayUnits( this->m_TextRenderer->GetRenderWindow()->GetSize()[0], this->m_TextRenderer->GetRenderWindow()->GetSize()[1] );
   this->GetDisplayGeometry()->Fit();
   this->GetVtkRenderer()->ResetCamera();
   this->Modified();
   return true;
 }
 
 
 /*!
 \brief
 
 Called by the vtkMitkRenderProp in order to start MITK rendering process.
 */
 int mitk::VtkPropRenderer::Render(mitk::VtkPropRenderer::RenderType type)
 {
 
   // Do we have objects to render?
   if ( this->GetEmptyWorldGeometry())
     return 0;
 
   if ( m_DataStorage.IsNull())
     return 0;
 
   // Update mappers and prepare mapper queue
   if (type == VtkPropRenderer::Opaque)
     this->PrepareMapperQueue();
 
   //go through the generated list and let the sorted mappers paint
   bool lastVtkBased = true;
   //bool sthVtkBased = false;
 
   for(MappersMapType::iterator it = m_MappersMap.begin(); it != m_MappersMap.end(); it++)
   {
     Mapper * mapper = (*it).second;
 
     VtkMapper* vtkmapper = dynamic_cast<VtkMapper*>(mapper);
 
     if(vtkmapper)
     {
       //sthVtkBased = true;
       if(!lastVtkBased)
       {
         Disable2DOpenGL();
         lastVtkBased = true;
       }
     }
     else
       if(lastVtkBased)
       {
       Enable2DOpenGL();
       lastVtkBased = false;
     }
 
   mapper->MitkRender(this, type);
 
   }
 
   this->UpdateOverlays();
 
   if (lastVtkBased == false)
     Disable2DOpenGL();
 
   // Render text
   if (type == VtkPropRenderer::Overlay)
   {
     if (m_TextCollection.size() > 0)
     {
       m_TextRenderer->SetViewport( this->GetVtkRenderer()->GetViewport() );
       for (TextMapType::iterator it = m_TextCollection.begin(); it != m_TextCollection.end() ; it++)
         m_TextRenderer->AddViewProp((*it).second);
       m_TextRenderer->Render();
     }
   }
   return 1;
 }
 
 /*!
 \brief PrepareMapperQueue iterates the datatree
 
 PrepareMapperQueue iterates the datatree in order to find mappers which shall be rendered. Also, it sortes the mappers wrt to their layer.
 */
 void mitk::VtkPropRenderer::PrepareMapperQueue()
 {
   // variable for counting LOD-enabled mappers
   m_NumberOfVisibleLODEnabledMappers = 0;
 
   // Do we have to update the mappers ?
   if ( m_LastUpdateTime < GetMTime() || m_LastUpdateTime < GetDisplayGeometry()->GetMTime() ) {
     Update();
   }
   else if (m_MapperID>=1 && m_MapperID < 6)
     Update();
 
   // remove all text properties before mappers will add new ones
   m_TextRenderer->RemoveAllViewProps();
 
   for ( unsigned int i=0; i<m_TextCollection.size(); i++ )
   {
     m_TextCollection[i]->Delete();
   }
   m_TextCollection.clear();
 
   // clear priority_queue
   m_MappersMap.clear();
 
   int mapperNo = 0;
 
   //DataStorage
   if( m_DataStorage.IsNull() )
     return;
 
   DataStorage::SetOfObjects::ConstPointer allObjects = m_DataStorage->GetAll();
 
   for (DataStorage::SetOfObjects::ConstIterator it = allObjects->Begin();  it != allObjects->End(); ++it)
   {
     DataNode::Pointer node = it->Value();
     if ( node.IsNull() )
       continue;
     mitk::Mapper::Pointer mapper = node->GetMapper(m_MapperID);
 
     if ( mapper.IsNull() )
       continue;
 
     bool visible = true;
     node->GetVisibility(visible, this, "visible");
 
     // The information about LOD-enabled mappers is required by RenderingManager
     if ( mapper->IsLODEnabled( this ) && visible )
     {
       ++m_NumberOfVisibleLODEnabledMappers;
     }
     // mapper without a layer property get layer number 1
     int layer = 1;
     node->GetIntProperty("layer", layer, this);
     int nr = (layer<<16) + mapperNo;
     m_MappersMap.insert( std::pair< int, Mapper * >( nr, mapper ) );
     mapperNo++;
   }
 }
 
 /*!
 \brief
 
 Enable2DOpenGL() and Disable2DOpenGL() are used to switch between 2D rendering (orthographic projection) and 3D rendering (perspective projection)
 */
 void mitk::VtkPropRenderer::Enable2DOpenGL()
 {
   GLint iViewport[4];
 
   // Get a copy of the viewport
   glGetIntegerv( GL_VIEWPORT, iViewport );
 
   // Save a copy of the projection matrix so that we can restore it
   // when it's time to do 3D rendering again.
   glMatrixMode( GL_PROJECTION );
   glPushMatrix();
   glLoadIdentity();
 
   // Set up the orthographic projection
   const DisplayGeometry* displayGeometry = this->GetDisplayGeometry();
 
   float displayGeometryWidth = displayGeometry->GetSizeInDisplayUnits()[0];
   float displayGeometryHeight = displayGeometry->GetSizeInDisplayUnits()[1];
   float viewportWidth = iViewport[2];
   float viewportHeight = iViewport[3];
 
   /*
      The following makes OpenGL mappers draw into the same viewport
      that is used by VTK when someone calls vtkRenderer::SetViewport().
 
      The parameters of glOrtho describe what "input" coordinates
      (display coordinates generated by the OpenGL mappers) are transformed
      into the region defined by the viewport. The call has to consider
      that the scene is fit vertically and centered horizontally.
 
      Problem: this is a crude first step towards rendering into viewports.
       - mitkViewportRenderingTest demonstrates the non-interactive rendering
         that is now possible
       - interactors that measure mouse movement in pixels will
         probably run into problems with display-to-world transformation
 
      A proper solution should probably modify the DisplayGeometry to
      correctly describe the viewport.
   */
   // iViewport is (x,y,width,height)
   // glOrtho expects (left,right,bottom,top,znear,zfar)
   glOrtho( 0
            - 0.5 * (viewportWidth/viewportHeight-1.0)*displayGeometryHeight
            + 0.5 * (displayGeometryWidth - displayGeometryHeight)
            ,
            displayGeometryWidth
            + 0.5 * (viewportWidth/viewportHeight-1.0)*displayGeometryHeight
            - 0.5 * (displayGeometryWidth - displayGeometryHeight)
            ,
            0, displayGeometryHeight,
       -1.0, 1.0
       );
 
   glMatrixMode( GL_MODELVIEW );
   glPushMatrix();
   glLoadIdentity();
 
   // Make sure depth testing and lighting are disabled for 2D rendering until
   // we are finished rendering in 2D
   glPushAttrib( GL_DEPTH_BUFFER_BIT | GL_LIGHTING_BIT );
   glDisable( GL_DEPTH_TEST );
   glDisable( GL_LIGHTING );
   // disable the texturing here so crosshair is painted in the correct colors
   // vtk will reenable texturing every time it is needed
   glDisable( GL_TEXTURE_1D );
   glDisable( GL_TEXTURE_2D );
   glLineWidth(1.0);
 }
 
 /*!
 \brief Initialize the VtkPropRenderer
 
 Enable2DOpenGL() and Disable2DOpenGL() are used to switch between 2D rendering (orthographic projection) and 3D rendering (perspective projection)
 */
 void mitk::VtkPropRenderer::Disable2DOpenGL()
 {
   glPopAttrib();
   glMatrixMode( GL_PROJECTION );
   glPopMatrix();
   glMatrixMode( GL_MODELVIEW );
   glPopMatrix();
 }
 
 
 void mitk::VtkPropRenderer::Update(mitk::DataNode* datatreenode)
 {
   if(datatreenode!=NULL)
   {
     mitk::Mapper::Pointer mapper = datatreenode->GetMapper(m_MapperID);
     if(mapper.IsNotNull())
     {
       GLMapper* glmapper=dynamic_cast<GLMapper*>(mapper.GetPointer());
 
       if(GetDisplayGeometry()->IsValid())
       {
         if(glmapper != NULL)
         {
           glmapper->Update(this);
           m_VtkMapperPresent=false;
         }
         else
         {
           VtkMapper* vtkmapper=dynamic_cast<VtkMapper*>(mapper.GetPointer());
           if(vtkmapper != NULL)
           {
             vtkmapper->Update(this);
             vtkmapper->UpdateVtkTransform(this);
             m_VtkMapperPresent=true;
           }
         }
       }
     }
   }
 }
 
 
 void mitk::VtkPropRenderer::Update()
 {
   if( m_DataStorage.IsNull() )
     return;
 
   m_VtkMapperPresent = false;
   mitk::DataStorage::SetOfObjects::ConstPointer all = m_DataStorage->GetAll();
   for (mitk::DataStorage::SetOfObjects::ConstIterator it = all->Begin(); it != all->End(); ++it)
     Update(it->Value());
 
   Modified();
   m_LastUpdateTime = GetMTime();
 }
 
 
 /*!
 \brief
 
 This method is called from the two Constructors
 */
 void mitk::VtkPropRenderer::InitRenderer(vtkRenderWindow* renderWindow)
 {
   BaseRenderer::InitRenderer(renderWindow);
 
   if(renderWindow == NULL)
   {
     m_InitNeeded = false;
     m_ResizeNeeded = false;
     return;
   }
 
   m_InitNeeded = true;
   m_ResizeNeeded = true;
 
   m_LastUpdateTime = 0;
 
 }
 
 
 /*!
 \brief Resize the OpenGL Window
 */
 void mitk::VtkPropRenderer::Resize(int w, int h)
 {
   BaseRenderer::Resize(w, h);
   m_RenderingManager->RequestUpdate(this->GetRenderWindow());
 }
 
 
 void mitk::VtkPropRenderer::InitSize(int w, int h)
 {
   m_RenderWindow->SetSize(w,h);
   Superclass::InitSize(w, h);
   Modified();
   Update();
   if(m_VtkRenderer!=NULL)
   {
     int w=vtkObject::GetGlobalWarningDisplay();
     vtkObject::GlobalWarningDisplayOff();
     m_VtkRenderer->ResetCamera();
     vtkObject::SetGlobalWarningDisplay(w);
   }
 }
 
 
 void mitk::VtkPropRenderer::SetMapperID(const MapperSlotId mapperId)
 {
   if(m_MapperID != mapperId)
     Superclass::SetMapperID(mapperId);
 
   // Workaround for GL Displaylist Bug
   checkState();
 }
 
 
 /*!
 \brief Activates the current renderwindow.
 */
 void mitk::VtkPropRenderer::MakeCurrent()
 {
   if(m_RenderWindow!=NULL)
     m_RenderWindow->MakeCurrent();
 }
 
 
 void mitk::VtkPropRenderer::PickWorldPoint(const mitk::Point2D& displayPoint, mitk::Point3D& worldPoint) const
 {
   if(m_VtkMapperPresent)
   {
     //m_WorldPointPicker->SetTolerance (0.0001);
     switch ( m_PickingMode )
     {
     case (WorldPointPicking) :
       {
         m_WorldPointPicker->Pick(displayPoint[0], displayPoint[1], 0, m_VtkRenderer);
         vtk2itk(m_WorldPointPicker->GetPickPosition(), worldPoint);
         break;
       }
     case (PointPicking) :
       {
         // create a new vtkRenderer
         // give it all necessary information (camera position, etc.)
         // get all surfaces from datastorage, get actors from them
         // add all those actors to the new renderer
         // give this new renderer to pointpicker
         /*
        vtkRenderer* pickingRenderer = vtkRenderer::New();
        pickingRenderer->SetActiveCamera( );
 
        DataStorage* dataStorage = m_DataStorage;
        TNodePredicateDataType<Surface> isSurface;
 
        DataStorage::SetOfObjects::ConstPointer allSurfaces = dataStorage->GetSubset( isSurface );
        MITK_INFO << "in picking: got " << allSurfaces->size() << " surfaces." << std::endl;
 
        for (DataStorage::SetOfObjects::const_iterator iter = allSurfaces->begin();
             iter != allSurfaces->end();
             ++iter)
        {
          const DataNode* currentNode = *iter;
          VtkMapper3D* baseVtkMapper3D = dynamic_cast<VtkMapper3D*>( currentNode->GetMapper( BaseRenderer::Standard3D ) );
          if ( baseVtkMapper3D )
          {
            vtkActor* actor = dynamic_cast<vtkActor*>( baseVtkMapper3D->GetViewProp() );
            if (actor)
            {
              MITK_INFO << "a" << std::flush;
              pickingRenderer->AddActor( actor );
            }
          }
        }
 
        MITK_INFO << ";" << std::endl;
        */
         m_PointPicker->Pick(displayPoint[0], displayPoint[1], 0, m_VtkRenderer);
         vtk2itk(m_PointPicker->GetPickPosition(), worldPoint);
         break;
       }
+    case(CellPicking) :
+      {
+        m_CellPicker->Pick(displayPoint[0], displayPoint[1], 0, m_VtkRenderer);
+        vtk2itk(m_CellPicker->GetPickPosition(), worldPoint);
+        break;
+      }
     }
   }
   else
   {
     Superclass::PickWorldPoint(displayPoint, worldPoint);
   }
 }
 
 mitk::DataNode *
     mitk::VtkPropRenderer::PickObject( const Point2D &displayPosition, Point3D &worldPosition ) const
 {
   if ( m_VtkMapperPresent )
   {
     m_CellPicker->InitializePickList();
 
     // Iterate over all DataStorage objects to determine all vtkProps intended
     // for picking
     DataStorage::SetOfObjects::ConstPointer allObjects = m_DataStorage->GetAll();
     for ( DataStorage::SetOfObjects::ConstIterator it = allObjects->Begin();
     it != allObjects->End();
     ++it )
     {
       DataNode *node = it->Value();
       if ( node == NULL )
         continue;
 
       bool pickable = false;
       node->GetBoolProperty( "pickable", pickable );
       if ( !pickable )
         continue;
 
       VtkMapper *mapper = dynamic_cast < VtkMapper * >  ( node->GetMapper( m_MapperID ) );
       if ( mapper == NULL )
         continue;
 
       vtkProp *prop = mapper->GetVtkProp( (mitk::BaseRenderer *)this );
       if ( prop == NULL )
         continue;
 
       m_CellPicker->AddPickList( prop );
     }
 
 
     // Do the picking and retrieve the picked vtkProp (if any)
     m_CellPicker->PickFromListOn();
     m_CellPicker->Pick( displayPosition[0], displayPosition[1], 0.0, m_VtkRenderer );
     m_CellPicker->PickFromListOff();
 
     vtk2itk( m_CellPicker->GetPickPosition(), worldPosition );
     vtkProp *prop = m_CellPicker->GetViewProp();
 
     if ( prop == NULL )
     {
       return NULL;
     }
 
     // Iterate over all DataStorage objects to determine if the retrieved
     // vtkProp is owned by any associated mapper.
     for ( DataStorage::SetOfObjects::ConstIterator it = allObjects->Begin();
     it != allObjects->End();
     ++it)
     {
       DataNode::Pointer node = it->Value();
       if ( node.IsNull() )
         continue;
 
       mitk::Mapper * mapper = node->GetMapper( m_MapperID );
       if ( mapper == NULL)
         continue;
 
       mitk::VtkMapper * vtkmapper = dynamic_cast< VtkMapper * >(mapper);
 
       if(vtkmapper){
         //if vtk-based, then ...
        if ( vtkmapper->HasVtkProp( prop, const_cast< mitk::VtkPropRenderer * >( this ) ) )
        {
           return node;
        }
       }
     }
 
     return NULL;
   }
   else
   {
     return Superclass::PickObject( displayPosition, worldPosition );
   }
 };
 
 
 
 /*!
 \brief Writes some 2D text as overlay. Function returns an unique int Text_ID for each call, which can be used via the GetTextLabelProperty(int text_id) function
 in order to get a vtkTextProperty. This property enables the setup of font, font size, etc.
 */
 int mitk::VtkPropRenderer::WriteSimpleText(std::string text, double posX, double posY, double color1, double color2, double color3, float opacity)
 {
   if(!text.empty())
   {
     Point2D p;
     p[0] = posX;
     p[1] = posY;
     p = TransformOpenGLPointToViewport(p);
 
     vtkTextActor* textActor = vtkTextActor::New();
 
     textActor->SetPosition(p[0], p[1]);
     textActor->SetInput(text.c_str());
     textActor->SetTextScaleModeToNone();
     textActor->GetTextProperty()->SetColor(color1, color2, color3); //TODO: Read color from node property
     textActor->GetTextProperty()->SetOpacity( opacity );
     int text_id = m_TextCollection.size();
     m_TextCollection.insert(TextMapType::value_type(text_id,textActor));
     return text_id;
   }
   else
   {
     return -1;
   }
 }
 
 
 /*!
 \brief Can be used in order to get a vtkTextProperty for a specific text_id. This property enables the setup of font, font size, etc.
 */
 vtkTextProperty* mitk::VtkPropRenderer::GetTextLabelProperty(int text_id)
 {
   return this->m_TextCollection[text_id]->GetTextProperty();
 }
 
 
 void mitk::VtkPropRenderer::InitPathTraversal()
 {
   if (m_DataStorage.IsNotNull())
   {
     m_PickingObjects = m_DataStorage->GetAll();
     m_PickingObjectsIterator = m_PickingObjects->begin();
   }
 }
 
 
 vtkAssemblyPath* mitk::VtkPropRenderer::GetNextPath()
 {
   if (m_DataStorage.IsNull() )
   {
     return NULL;
   }
 
   if ( m_PickingObjectsIterator == m_PickingObjects->end() )
   {
     return NULL;
   }
 
   vtkAssemblyPath* returnPath = vtkAssemblyPath::New();
   //returnPath->Register(NULL);
 
   bool success = false;
 
   while (!success)
   {
     // loop until AddNode can be called successfully
     const DataNode* node = *m_PickingObjectsIterator;
     if (node)
     {
       Mapper* mapper = node->GetMapper( BaseRenderer::Standard3D );
       if (mapper)
       {
         VtkMapper* vtkmapper = dynamic_cast<VtkMapper*>( mapper );
         if (vtkmapper)
         {
           vtkProp* prop = vtkmapper->GetVtkProp(this);
           if ( prop && prop->GetVisibility() )
           {
             // add to assembly path
             returnPath->AddNode( prop, prop->GetMatrix() );
             success = true;
           }
         }
       }
     }
 
     ++m_PickingObjectsIterator;
 
     if ( m_PickingObjectsIterator == m_PickingObjects->end() ) break;
   }
 
   if ( success )
   {
     return returnPath;
   }
   else
   {
     return NULL;
   }
 }
 
 
 void mitk::VtkPropRenderer::ReleaseGraphicsResources(vtkWindow *renWin)
 {
   if( m_DataStorage.IsNull() )
     return;
 
   DataStorage::SetOfObjects::ConstPointer allObjects = m_DataStorage->GetAll();
   for (DataStorage::SetOfObjects::const_iterator iter = allObjects->begin(); iter != allObjects->end(); ++iter)
   {
     DataNode::Pointer node = *iter;
     if ( node.IsNull() )
       continue;
 
       Mapper * mapper = node->GetMapper(m_MapperID);
 
       if (mapper)
       {
         VtkMapper* vtkmapper = dynamic_cast<VtkMapper*>( mapper );
 
        if(vtkmapper)
          vtkmapper->ReleaseGraphicsResources(renWin);
       }
    }
 }
 
 
 const vtkWorldPointPicker *mitk::VtkPropRenderer::GetWorldPointPicker() const
 {
   return m_WorldPointPicker;
 }
 
 
 const vtkPointPicker *mitk::VtkPropRenderer::GetPointPicker() const
 {
   return m_PointPicker;
 }
 
 
 const vtkCellPicker *mitk::VtkPropRenderer::GetCellPicker() const
 {
   return m_CellPicker;
 }
 
 
 mitk::VtkPropRenderer::MappersMapType mitk::VtkPropRenderer::GetMappersMap() const
 {
   return m_MappersMap;
 }
 
 
 // Workaround for GL Displaylist bug
 
 static int glWorkAroundGlobalCount = 0;
 
 bool mitk::VtkPropRenderer::useImmediateModeRendering()
 {
   return glWorkAroundGlobalCount>1;
 }
 
 void mitk::VtkPropRenderer::checkState()
 {
   if (m_MapperID == Standard3D)
   {
     if (!didCount)
     {
       didCount = true;
       glWorkAroundGlobalCount++;
 
       if (glWorkAroundGlobalCount == 2)
       {
         MITK_INFO << "Multiple 3D Renderwindows active...: turning Immediate Rendering ON for legacy mappers";
         //          vtkMapper::GlobalImmediateModeRenderingOn();
       }
       //MITK_INFO << "GLOBAL 3D INCREASE " << glWorkAroundGlobalCount << "\n";
 
     }
   }
   else
   {
     if(didCount)
     {
       didCount=false;
       glWorkAroundGlobalCount--;
       if(glWorkAroundGlobalCount==1)
       {
         MITK_INFO << "Single 3D Renderwindow active...: turning Immediate Rendering OFF for legacy mappers";
         //        vtkMapper::GlobalImmediateModeRenderingOff();
       }
       //MITK_INFO << "GLOBAL 3D DECREASE " << glWorkAroundGlobalCount << "\n";
     }
   }
 }
 
 //### Contains all methods which are neceassry before each VTK Render() call
 void mitk::VtkPropRenderer::PrepareRender()
 {
   if ( this->GetMapperID() != m_CameraInitializedForMapperID )
   {
     Initialize2DvtkCamera(); //Set parallel projection etc.
   }
 
   AdjustCameraToScene(); //Prepare camera for 2D render windows
 }
 
 bool mitk::VtkPropRenderer::Initialize2DvtkCamera()
 {
   if ( this->GetMapperID() == Standard3D )
   {
     //activate parallel projection for 2D
     this->GetVtkRenderer()->GetActiveCamera()->SetParallelProjection(false);
     this->GetRenderWindow()->GetInteractor()->SetInteractorStyle( vtkInteractorStyleTrackballCamera::New() );
     m_CameraInitializedForMapperID = Standard3D;
   }
   else if( this->GetMapperID() == Standard2D)
   {
     //activate parallel projection for 2D
     this->GetVtkRenderer()->GetActiveCamera()->SetParallelProjection(true);
     //turn the light out in the scene in order to render correct grey values.
     //TODO Implement a property for light in the 2D render windows (in another method)
     this->GetVtkRenderer()->RemoveAllLights();
 
     this->GetRenderWindow()->GetInteractor()->SetInteractorStyle( mitkVtkInteractorStyle::New() );
 
     m_CameraInitializedForMapperID = Standard2D;
   }
   return true;
 }
 
 void mitk::VtkPropRenderer::AdjustCameraToScene(){
   if(this->GetMapperID() == Standard2D)
   {
     const mitk::DisplayGeometry* displayGeometry = this->GetDisplayGeometry();
 
     double objectHeightInMM = this->GetCurrentWorldGeometry2D()->GetExtentInMM(1);//the height of the current object slice in mm
     double displayHeightInMM = displayGeometry->GetSizeInMM()[1]; //the display height in mm (gets smaller when you zoom in)
     double zoomFactor = objectHeightInMM/displayHeightInMM; //displayGeometry->GetScaleFactorMMPerDisplayUnit()
     //determine how much of the object can be displayed
 
     Vector2D displayGeometryOriginInMM = displayGeometry->GetOriginInMM();  //top left of the render window (Origin)
     Vector2D displayGeometryCenterInMM = displayGeometryOriginInMM + displayGeometry->GetSizeInMM()*0.5; //center of the render window: (Origin + Size/2)
 
     //Scale the rendered object:
     //The image is scaled by a single factor, because in an orthographic projection sizes
     //are preserved (so you cannot scale X and Y axis with different parameters). The
     //parameter sets the size of the total display-volume. If you set this to the image
     //height, the image plus a border with the size of the image will be rendered.
     //Therefore, the size is imageHeightInMM / 2.
     this->GetVtkRenderer()->GetActiveCamera()->SetParallelScale(objectHeightInMM*0.5 );
     //zooming with the factor calculated by dividing displayHeight through imegeHeight. The factor is inverse, because the VTK zoom method is working inversely.
     this->GetVtkRenderer()->GetActiveCamera()->Zoom(zoomFactor);
 
     //the center of the view-plane
     double viewPlaneCenter[3];
     viewPlaneCenter[0] = displayGeometryCenterInMM[0];
     viewPlaneCenter[1] = displayGeometryCenterInMM[1];
     viewPlaneCenter[2] = 0.0; //the view-plane is located in the XY-plane with Z=0.0
 
     //define which direction is "up" for the ciamera (like default for vtk (0.0, 1.0, 0.0)
     double cameraUp[3];
     cameraUp[0] = 0.0;
     cameraUp[1] = 1.0;
     cameraUp[2] = 0.0;
 
     //the position of the camera (center[0], center[1], 900000)
     double cameraPosition[3];
     cameraPosition[0] = viewPlaneCenter[0];
     cameraPosition[1] = viewPlaneCenter[1];
     cameraPosition[2] = 900000.0; //Reason for 900000: VTK seems to calculate the clipping planes wrong for small values. See VTK bug (id #7823) in VTK bugtracker.
 
     //set the camera corresponding to the textured plane
     vtkSmartPointer<vtkCamera> camera = this->GetVtkRenderer()->GetActiveCamera();
     if (camera)
     {
       camera->SetPosition( cameraPosition ); //set the camera position on the textured plane normal (in our case this is the view plane normal)
       camera->SetFocalPoint( viewPlaneCenter ); //set the focal point to the center of the textured plane
       camera->SetViewUp( cameraUp ); //set the view-up for the camera
       //      double distance = sqrt((cameraPosition[2]-viewPlaneCenter[2])*(cameraPosition[2]-viewPlaneCenter[2]));
       //      camera->SetClippingRange(distance-50, distance+50); //Reason for huge range: VTK seems to calculate the clipping planes wrong for small values. See VTK bug (id #7823) in VTK bugtracker.
       camera->SetClippingRange(0.1, 1000000); //Reason for huge range: VTK seems to calculate the clipping planes wrong for small values. See VTK bug (id #7823) in VTK bugtracker.
     }
 
     const PlaneGeometry *planeGeometry = dynamic_cast< const PlaneGeometry * >( this->GetCurrentWorldGeometry2D() );
     if ( planeGeometry != NULL )
     {
       //Transform the camera to the current position (transveral, coronal and saggital plane).
       //This is necessary, because the SetUserTransform() method does not manipulate the vtkCamera.
       //(Without not all three planes would be visible).
       vtkSmartPointer<vtkTransform> trans = vtkSmartPointer<vtkTransform>::New();
       vtkSmartPointer<vtkMatrix4x4> matrix = vtkSmartPointer<vtkMatrix4x4>::New();
       Point3D origin;
       Vector3D right, bottom, normal;
 
       origin = planeGeometry->GetOrigin();
       right  = planeGeometry->GetAxisVector( 0 ); // right = Extent of Image in mm (worldspace)
       bottom = planeGeometry->GetAxisVector( 1 );
       normal = planeGeometry->GetNormal();
 
       right.Normalize();
       bottom.Normalize();
       normal.Normalize();
 
       matrix->SetElement(0, 0, right[0]);
       matrix->SetElement(1, 0, right[1]);
       matrix->SetElement(2, 0, right[2]);
       matrix->SetElement(0, 1, bottom[0]);
       matrix->SetElement(1, 1, bottom[1]);
       matrix->SetElement(2, 1, bottom[2]);
       matrix->SetElement(0, 2, normal[0]);
       matrix->SetElement(1, 2, normal[1]);
       matrix->SetElement(2, 2, normal[2]);
       matrix->SetElement(0, 3, origin[0]);
       matrix->SetElement(1, 3, origin[1]);
       matrix->SetElement(2, 3, origin[2]);
       matrix->SetElement(3, 0, 0.0);
       matrix->SetElement(3, 1, 0.0);
       matrix->SetElement(3, 2, 0.0);
       matrix->SetElement(3, 3, 1.0);
 
       trans->SetMatrix(matrix);
       //Transform the camera to the current position (transveral, coronal and saggital plane).
       this->GetVtkRenderer()->GetActiveCamera()->ApplyTransform(trans);
     }
   }
 }
 
 mitk::Point2D mitk::VtkPropRenderer::TransformOpenGLPointToViewport( mitk::Point2D point )
 {
   GLint iViewport[4];
   // Get a copy of the viewport
   glGetIntegerv( GL_VIEWPORT, iViewport );
   const mitk::DisplayGeometry* displayGeometry = this->GetDisplayGeometry();
 
   float displayGeometryWidth = displayGeometry->GetSizeInDisplayUnits()[0];
   float displayGeometryHeight = displayGeometry->GetSizeInDisplayUnits()[1];
 
   float viewportWidth = iViewport[2];
   float viewportHeight = iViewport[3]; // seemingly right
 
   float zoom = viewportHeight / displayGeometryHeight;
 
   // see glOrtho call above for more explanation
   point[0] +=
     0.5 * (viewportWidth/viewportHeight-1.0)*displayGeometryHeight
     - 0.5 * (displayGeometryWidth - displayGeometryHeight)
     ;
 
   point[0] *= zoom;
   point[1] *= zoom;
 
   return point;
 }
diff --git a/Core/Code/Rendering/mitkVtkPropRenderer.h b/Core/Code/Rendering/mitkVtkPropRenderer.h
index b345ddd335..d37cb46627 100644
--- a/Core/Code/Rendering/mitkVtkPropRenderer.h
+++ b/Core/Code/Rendering/mitkVtkPropRenderer.h
@@ -1,250 +1,260 @@
 /*===================================================================
 
 The Medical Imaging Interaction Toolkit (MITK)
 
 Copyright (c) German Cancer Research Center,
 Division of Medical and Biological Informatics.
 All rights reserved.
 
 This software is distributed WITHOUT ANY WARRANTY; without
 even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.
 
 See LICENSE.txt or http://www.mitk.org for details.
 
 ===================================================================*/
 
 
 #ifndef MITKVtkPropRenderer_H_HEADER_INCLUDED_C1C29F6D
 #define MITKVtkPropRenderer_H_HEADER_INCLUDED_C1C29F6D
 
 #include <MitkExports.h>
 #include "mitkBaseRenderer.h"
 #include "mitkDataStorage.h"
 #include "mitkRenderingManager.h"
 
 #include <itkCommand.h>
 
 #include <map>
 #include <utility>
 
 class vtkRenderWindow;
 class vtkLight;
 class vtkLightKit;
 class vtkWorldPointPicker;
 class vtkPointPicker;
 class vtkCellPicker;
 class vtkTextActor;
 class vtkTextProperty;
 class vtkAssemblyPath;
 
 
 namespace mitk
 {
 
 class Mapper;
 
 /*!
 \brief VtkPropRenderer
 
 VtkPropRenderer organizes the MITK rendering process. The MITK rendering process is completely integrated into the VTK rendering pipeline.
 The vtkMitkRenderProp is a custom vtkProp derived class, which implements the rendering interface between MITK and VTK. It redirects render() calls to the VtkPropRenderer, which is responsible for rendering of the datatreenodes.
 VtkPropRenderer replaces the old OpenGLRenderer.
 
 \sa rendering
 \ingroup rendering
 */
 class MITK_CORE_EXPORT VtkPropRenderer : public BaseRenderer
 {
   // Workaround for Displaylistbug
 private:
   bool didCount;
   void checkState();
 
   // Workaround END
 
 public:
 
   mitkClassMacro(VtkPropRenderer,BaseRenderer);
   mitkNewMacro3Param(VtkPropRenderer, const char*, vtkRenderWindow *, mitk::RenderingManager* );
 
   typedef std::map<int,Mapper*> MappersMapType;
 
   // Render - called by vtkMitkRenderProp, returns the number of props rendered
   enum RenderType{Opaque,Translucent,Overlay,Volumetric};
 
   int Render(RenderType type);
 
   /** \brief This methods contains all method neceassary before a VTK Render() call */
   virtual void PrepareRender();
 
   // Active current renderwindow
   virtual void MakeCurrent();
 
   virtual void SetDataStorage( mitk::DataStorage* storage );  ///< set the datastorage that will be used for rendering
 
   virtual void InitRenderer(vtkRenderWindow* renderwindow);
   virtual void Update(mitk::DataNode* datatreenode);
   virtual void SetMapperID(const MapperSlotId mapperId);
 
   // Size
   virtual void InitSize(int w, int h);
   virtual void Resize(int w, int h);
 
   // Picking
-  enum PickingMode{ WorldPointPicking, PointPicking };
+  enum PickingMode{ WorldPointPicking, PointPicking, CellPicking};
+  /** \brief  Set the picking mode.
+  This method is used to set the picking mode for 3D object picking. The user can select one of
+  the three options WorldPointPicking, PointPicking and CellPicking. The first option uses the zBuffer
+  from graphics rendering, the second uses the 3D points from the closest surface mesh, and the third
+  option uses the cells   of that mesh. The last option is the slowest, the first one the fastest.
+  However, the first option cannot use transparent data object and the tolerance of the picked position
+  to the selected point should be considered. PointPicking also need a tolerance around the picking
+  position to select the closest point in the mesh. The CellPicker performs very well, if the
+  foreground surface part (i.e. the surfacepart that is closest to the scene's cameras) needs to be
+  picked. */
   itkSetEnumMacro( PickingMode, PickingMode );
   itkGetEnumMacro( PickingMode, PickingMode );
 
   virtual void PickWorldPoint(const Point2D& displayPoint, Point3D& worldPoint) const;
   virtual mitk::DataNode *PickObject( const Point2D &displayPosition, Point3D &worldPosition ) const;
 
   // Simple text rendering method
   int WriteSimpleText(std::string text, double posX, double posY, double color1 = 0.0, double color2 = 1.0, double color3 = 0.0, float opacity = 1.0);
 
   vtkTextProperty * GetTextLabelProperty(int text_id);
 
   // Initialization / geometry handling
 
   /** This method calculates the bounds of the DataStorage (if it contains any
    * valid data), creates a geometry from these bounds and sets it as world
    * geometry of the renderer.
    *
    * Call this method to re-initialize the renderer to the current DataStorage
    * (e.g. after loading an additional dataset), to ensure that the view is
    * aligned correctly.
    */
   virtual bool SetWorldGeometryToDataStorageBounds();
 
   /**
    * \brief Used by vtkPointPicker/vtkPicker.
    * This will query a list of all objects in MITK and provide every vtk based mapper to the picker.
    */
   void InitPathTraversal();
 
   /**
    * \brief Used by vtkPointPicker/vtkPicker.
    * This will query a list of all objects in MITK and provide every vtk based mapper to the picker.
    */
   vtkAssemblyPath* GetNextPath();
 
   const vtkWorldPointPicker *GetWorldPointPicker() const;
   const vtkPointPicker *GetPointPicker() const;
   const vtkCellPicker *GetCellPicker() const;
 
   /**
   * \brief Release vtk-based graphics resources. Called by
   * vtkMitkRenderProp::ReleaseGraphicsResources.
   */
   virtual void ReleaseGraphicsResources(vtkWindow *renWin);
 
   MappersMapType GetMappersMap() const;
 
   static bool useImmediateModeRendering();
 
 protected:
   VtkPropRenderer( const char* name = "VtkPropRenderer", vtkRenderWindow * renWin = NULL, mitk::RenderingManager* rm = NULL );
   virtual ~VtkPropRenderer();
   virtual void Update();
 
   /**
     \brief Convert display geometry coordinates to VTK coordinates.
 
     For use within WriteSimpleText: the input is display geometry coordinates
     but the text actor needs positions that fit in a specified viewport.
     Conversion is done in this method.
   */
   mitk::Point2D TransformOpenGLPointToViewport( mitk::Point2D point );
 
 
 private:
 
   /** \brief This method sets up the camera on the actor (e.g. an image) of all
   * 2D vtkRenderWindows. The view is centered; zooming and panning of VTK are called inside.
   *
   * \image html ImageMapperdisplayGeometry.png
   *
   * Similar to the textured plane of an image
   * (cf. void mitkImageVtkMapper2D::GeneratePlane(mitk::BaseRenderer* renderer,
   * vtkFloatingPointType planeBounds[6])), the mitkDisplayGeometry defines a view plane (or
   * projection plane). This plane is used to set the camera parameters. The view plane
   * center (VC) is important for camera positioning (cf. the image above).
   *
   * The following figure shows the combination of the textured plane and the view plane.
   *
   * \image html cameraPositioning.png
   *
   * The view plane center (VC) is the center of the textured plane (C) and the focal point
   * (FP) at the same time. The FP defines the direction the camera faces. Since
   * the textured plane is always in the XY-plane and orthographic projection is applied, the
   * distance between camera and plane is theoretically irrelevant (because in the orthographic
   * projection the center of projection is at infinity and the size of objects depends only on
   * a scaling parameter). As a consequence, the direction of projection (DOP) is (0; 0; -1).
   * The camera up vector is always defined as (0; 1; 0).
   *
   * \warning Due to a VTK clipping bug the distance between textured plane and camera is really huge.
   * Otherwise, VTK would clip off some slices. Same applies for the clipping range size.
   *
   * \note The camera position is defined through the mitkDisplayGeometry.
   * This facilitates zooming and panning, because the display
   * geometry changes and the textured plane does not.
   *
   * \image html scaling.png
   *
   * The textured plane is scaled to fill the render window via
   * camera->SetParallelScale( imageHeightInMM / 2). In the orthographic projection all extends,
   * angles and sizes are preserved. Therefore, the image is scaled by one parameter which defines
   * the size of the rendered image. A higher value will result in smaller images. In order to render
   * just the whole image, the scale is set to half of the image height in worldcoordinates
   * (cf. the picture above).
   *
   * For zooming purposes, a factor is computed as follows:
   * factor = image height / display height (in worldcoordinates).
   * When the display geometry gets smaller (zoom in), the factor becomes bigger. When the display
   * geometry gets bigger (zoom out), the factor becomes smaller. The used VTK method
   * camera->Zoom( factor ) also works with an inverse scale.
   */
   void AdjustCameraToScene();
 
   // switch between orthogonal opengl projection (2D rendering via mitk::GLMapper2D) and perspective projection (3D rendering)
   void Enable2DOpenGL();
   void Disable2DOpenGL();
 
   // prepare all mitk::mappers for rendering
   void PrepareMapperQueue();
 
   /** \brief Set parallel projection, remove the interactor and the lights of VTK. */
   bool Initialize2DvtkCamera();
 
   bool m_InitNeeded;
   bool m_ResizeNeeded;
   bool m_VtkMapperPresent;
   MapperSlotId m_CameraInitializedForMapperID;
 
   // Picking
   vtkWorldPointPicker     * m_WorldPointPicker;
   vtkPointPicker          * m_PointPicker;
   vtkCellPicker           * m_CellPicker;
 
   PickingMode               m_PickingMode;
 
   // Explicit use of SmartPointer to avoid circular #includes
   itk::SmartPointer< mitk::Mapper > m_CurrentWorldGeometry2DMapper;
 
   vtkLightKit* m_LightKit;
 
   // sorted list of mappers
   MappersMapType m_MappersMap;
 
   // rendering of text
   vtkRenderer * m_TextRenderer;
   typedef std::map<unsigned int,vtkTextActor*> TextMapType;
   TextMapType m_TextCollection;
 
   DataStorage::SetOfObjects::ConstPointer m_PickingObjects;
   DataStorage::SetOfObjects::const_iterator m_PickingObjectsIterator;
 };
 
 } // namespace mitk
 
 #endif /* MITKVtkPropRenderer_H_HEADER_INCLUDED_C1C29F6D */