diff --git a/Modules/Overlays/QmitkScalarBarOverlay.cpp b/Modules/Overlays/QmitkScalarBarOverlay.cpp
index 2f3962d86e..954d75681c 100644
--- a/Modules/Overlays/QmitkScalarBarOverlay.cpp
+++ b/Modules/Overlays/QmitkScalarBarOverlay.cpp
@@ -1,119 +1,121 @@
 /*===================================================================
 
 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 "QmitkScalarBarOverlay.h"
 
 #include "mitkProperties.h"
 #include "mitkColorProperty.h"
 #include "mitkPropertyList.h"
 
 #include <itkCommand.h>
 
 #include <QLayout>
 
 
 QmitkScalarBarOverlay::QmitkScalarBarOverlay( const char* id ) 
 :QmitkOverlay(id)
 , m_ScalarBar( NULL )
 , m_ObserverTag(0)
 {
   m_Widget = m_ScalarBar = new QmitkScalarBar();
   QmitkOverlay::AddDropShadow( m_ScalarBar );
 }
 
 QmitkScalarBarOverlay::~QmitkScalarBarOverlay()
 {
   m_PropertyList->GetProperty( m_Id )->RemoveObserver(m_ObserverTag);
 }
 
 void QmitkScalarBarOverlay::GenerateData( mitk::PropertyList::Pointer pl )
 {
   if ( pl.IsNull() )
     return;
 
   m_PropertyList = pl;
 
   if ( m_PropertyList.IsNotNull() )
   {
     this->SetupCallback( m_PropertyList->GetProperty( m_Id ) );
 
     this->GetProperties( pl );
     this->SetScaleFactor();
   }
   else
   {
     MITK_DEBUG << "invalid propList";
   }
 
 }
 
 void QmitkScalarBarOverlay::SetScaleFactor()
 {
   float scale = 2;
   if ( m_PropertyList.IsNull() || !m_PropertyList->GetFloatProperty( m_Id, scale ) )
   {
     MITK_DEBUG << "Property " << m_Id << " could not be found";
   }
   m_ScalarBar->SetScaleFactor( scale );
 }
 
 
 void QmitkScalarBarOverlay::GetProperties( mitk::PropertyList::Pointer pl )
 {
   if ( pl.IsNull() )
     return;
 
   QPen pen = QPen();
 
 
   mitk::PropertyList::Pointer propertyList = pl;
   QPalette palette = QPalette();
 
   // get the desired color of the textOverlays
   mitk::ColorProperty::Pointer colorProp = 
     dynamic_cast<mitk::ColorProperty*>( propertyList->GetProperty( "overlay.color" ) );
 
   if ( colorProp.IsNull() )
   {
     MITK_DEBUG << "creating new colorProperty";
     colorProp = mitk::ColorProperty::New( 127.0, 196.0, 232.0 );
   }
 
   mitk::Color color = colorProp->GetColor();
   pen.setColor( QColor( color[0],color[1],color[2],255 ) );
   pen.setStyle( Qt::SolidLine );
   pen.setCapStyle( Qt::FlatCap );
   pen.setJoinStyle( Qt::MiterJoin );
 
   m_ScalarBar->SetPen( pen );
 }
 
 void QmitkScalarBarOverlay::SetupCallback( mitk::BaseProperty::Pointer prop )
 {
   if ( prop.IsNotNull() )
   {
+    prop->RemoveObserver(m_ObserverTag);
+
     typedef itk::SimpleMemberCommand< QmitkScalarBarOverlay > MemberCommandType;
     MemberCommandType::Pointer propModifiedCommand;
     propModifiedCommand = MemberCommandType::New();
     propModifiedCommand->SetCallbackFunction( this, &QmitkScalarBarOverlay::SetScaleFactor );
     m_ObserverTag = prop->AddObserver( itk::ModifiedEvent(), propModifiedCommand );
   }
   else
   {
     MITK_DEBUG << "invalid property";
   }
 }
 
diff --git a/Modules/Overlays/QmitkTextOverlay.cpp b/Modules/Overlays/QmitkTextOverlay.cpp
index bb9fd099ac..6660f48dd1 100644
--- a/Modules/Overlays/QmitkTextOverlay.cpp
+++ b/Modules/Overlays/QmitkTextOverlay.cpp
@@ -1,147 +1,149 @@
 /*===================================================================
 
 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 "QmitkTextOverlay.h"
 
 #include "mitkProperties.h"
 #include "mitkColorProperty.h"
 #include "mitkPropertyList.h"
 
 #include <itkCommand.h>
 
 QmitkTextOverlay::QmitkTextOverlay( const char* id )
 : QmitkOverlay(id)
 , m_ObserverTag(0)
 {
   m_Widget = m_Label = new QLabel();
   QmitkOverlay::AddDropShadow( m_Widget );
 }
 
 QmitkTextOverlay::~QmitkTextOverlay()
 {
   m_PropertyList->GetProperty( m_Id )->RemoveObserver(m_ObserverTag);
 }
 
 void QmitkTextOverlay::GenerateData( mitk::PropertyList::Pointer pl )
 {
   if ( pl.IsNull() )
     return;
 
   m_PropertyList = pl;
 
   if ( m_PropertyList.IsNotNull() )
   {
     this->SetupCallback( m_PropertyList->GetProperty( m_Id ) );
 
     this->UpdateFontProperties( pl );
     this->UpdateDisplayedTextFromProperties();
   }
   else
   {
     MITK_ERROR << "invalid propList";
   }
 
 }
 
 void QmitkTextOverlay::UpdateDisplayedTextFromProperties()
 {
   std::string text;
   if ( m_PropertyList.IsNull() || !m_PropertyList->GetStringProperty( m_Id, text ) )
   {
     MITK_DEBUG << "Property " << m_Id << " could not be found";
   }
   m_Label->setText( text.c_str() );
   m_Label->repaint();
 }
 
 
 void QmitkTextOverlay::UpdateFontProperties( mitk::PropertyList::Pointer pl )
 {
   if ( pl.IsNull() )
     return;
 
   mitk::PropertyList::Pointer propertyList = pl;
   QPalette palette = QPalette();
   QFont font = QFont();
 
   // get the desired color of the textOverlays
   mitk::ColorProperty::Pointer colorProp = 
     dynamic_cast<mitk::ColorProperty*>( propertyList->GetProperty( "overlay.color" ) );
 
   if ( colorProp.IsNull() )
   {
     colorProp = mitk::ColorProperty::New( 127.0, 196.0, 232.0 );
   }
 
   mitk::Color color = colorProp->GetColor();
   palette.setColor( QPalette::Foreground, QColor( color[0],color[1],color[2],255 ) );
   palette.setColor( QPalette::Window, Qt::transparent);
   m_Label->setPalette( palette );
 
   // get the desired opacity of the overlays
   //mitk::FloatProperty::Pointer opacityProperty =
   //  dynamic_cast<mitk::FloatProperty*>( propertyList->GetProperty( "overlay.opacity" ) );
 
   //if ( opacityProperty.IsNull() )
   //{
   //  m_Label->setWindowOpacity( 1 );
   //} 
   //else
   //{
   //  m_Label->setWindowOpacity( opacityProperty->GetValue() );
   //}
   
    //set the desired font-size of the overlays
   int fontSize = 0;
   if ( !propertyList->GetIntProperty( "overlay.fontSize", fontSize ) )
   {
     fontSize = 9.5;
   } 
   font.setPointSize( fontSize );
 
   bool useKerning = false;
   if ( !propertyList->GetBoolProperty( "overlay.kerning", useKerning ) )
   {
     useKerning = true;
   }
   font.setKerning( useKerning );
 
   std::string fontFamily = "";
   if ( !propertyList->GetStringProperty( "overlay.fontFamily", fontFamily ) )
   {
     fontFamily = "Verdana";
   }
   font.setFamily(  QString(fontFamily.c_str()) );
 
   m_Label->setFont( font );
 }
 
 void QmitkTextOverlay::SetupCallback( mitk::BaseProperty::Pointer prop )
 {
   if ( prop.IsNotNull() )
   {
+    prop->RemoveObserver(m_ObserverTag);
+
     typedef itk::SimpleMemberCommand< QmitkTextOverlay > MemberCommandType;
     MemberCommandType::Pointer propModifiedCommand;
     propModifiedCommand = MemberCommandType::New();
     propModifiedCommand->SetCallbackFunction( this, &QmitkTextOverlay::UpdateDisplayedTextFromProperties );
     m_ObserverTag = prop->AddObserver( itk::ModifiedEvent(), propModifiedCommand );
   }
   else
   {
     MITK_DEBUG << "invalid property";
   }
 }