diff --git a/Core/Code/Testing/mitkLevelWindowManagerTest.cpp b/Core/Code/Testing/mitkLevelWindowManagerTest.cpp
index 1f20838f58..7998d1b785 100644
--- a/Core/Code/Testing/mitkLevelWindowManagerTest.cpp
+++ b/Core/Code/Testing/mitkLevelWindowManagerTest.cpp
@@ -1,135 +1,162 @@
 /*===================================================================
 
 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 "mitkLevelWindowManager.h"
 #include "mitkStandaloneDataStorage.h"
 #include <mitkTestingMacros.h>
+#include <mitkIOUtil.h>
 
 class mitkLevelWindowManagerTestClass
 {
 public:
 
   static void TestInstantiation()
   {
   mitk::LevelWindowManager::Pointer manager;
   manager = mitk::LevelWindowManager::New();
   MITK_TEST_CONDITION_REQUIRED(manager.IsNotNull(),"Testing mitk::LevelWindowManager::New()");
   }
 
   static void TestSetGetDataStorage()
   {
   mitk::LevelWindowManager::Pointer manager;
   manager = mitk::LevelWindowManager::New();
   MITK_TEST_OUTPUT(<< "Creating DataStorage: ");
   mitk::StandaloneDataStorage::Pointer ds = mitk::StandaloneDataStorage::New();
 
   bool success = true;
   try
     {
     manager->SetDataStorage(ds);
     }
   catch(std::exception e)
     {
     success = false;
     MITK_ERROR << "Exception: " << e.what();
     }
   MITK_TEST_CONDITION_REQUIRED(success,"Testing mitk::LevelWindowManager SetDataStorage() ");
   MITK_TEST_CONDITION_REQUIRED(ds == manager->GetDataStorage(),"Testing mitk::LevelWindowManager GetDataStorage ");
 
   }
 
   static void TestMethodsWithInvalidParameters()
   {
   mitk::LevelWindowManager::Pointer manager;
   manager = mitk::LevelWindowManager::New();
   mitk::StandaloneDataStorage::Pointer ds = mitk::StandaloneDataStorage::New();
   manager->SetDataStorage(ds);
 
   /* commented out because of bug 13894
   success = false;
   try
     {
     mitk::LevelWindowProperty::Pointer levelWindowProperty = mitk::LevelWindowProperty::New();
     manager->SetLevelWindowProperty(levelWindowProperty);
     }
   catch(mitk::Exception e)
     {
     success = true;
     }
   MITK_TEST_CONDITION(success,"Testing mitk::LevelWindowManager SetLevelWindowProperty with invalid parameter");
   */
 
 
   /* TODO: convert the rest of this test to MITK testing macros when bug 13894 is fixed
   std::cout << "Testing mitk::LevelWindowManager GetLevelWindowProperty ";
   if (levelWindowProperty != manager->GetLevelWindowProperty())
   {
     std::cout<<"[FAILED]"<<std::endl;
     return EXIT_FAILURE;
   }
   std::cout<<"[PASSED]"<<std::endl;
   std::cout << "Testing mitk::LevelWindowManager isAutoTopMost ";
   if (manager->isAutoTopMost())
   {
     std::cout<<"[FAILED]"<<std::endl;
     return EXIT_FAILURE;
   }
   std::cout<<"[PASSED]"<<std::endl;
 
   std::cout << "Testing mitk::LevelWindowManager GetLevelWindow ";
   try
   {
     const mitk::LevelWindow levelWindow = manager->GetLevelWindow();
     std::cout<<"[PASSED]"<<std::endl;
 
     std::cout << "Testing mitk::LevelWindowManager SetLevelWindow ";
     manager->SetLevelWindow(levelWindow);
     std::cout<<"[PASSED]"<<std::endl;
   }
   catch (...)
   {
     std::cout<<"[FAILED]"<<std::endl;
     return EXIT_FAILURE;
   }
 
   std::cout << "Testing mitk::LevelWindowManager SetAutoTopMostImage ";
   manager->SetAutoTopMostImage(true);
   std::cout<<"[PASSED]"<<std::endl;
   std::cout << "Testing mitk::LevelWindowManager isAutoTopMost ";
   if (!(manager->isAutoTopMost()))
   {
     std::cout<<"[FAILED]"<<std::endl;
     return EXIT_FAILURE;
   }
   std::cout<<"[PASSED]"<<std::endl;
 
   std::cout<<"[TEST DONE]"<<std::endl;
   return EXIT_SUCCESS;
   }
   */
   }
 
+  static void TestRemoveObserver()
+  {
+  mitk::LevelWindowManager::Pointer manager;
+  manager = mitk::LevelWindowManager::New();
+  mitk::StandaloneDataStorage::Pointer ds = mitk::StandaloneDataStorage::New();
+  manager->SetDataStorage(ds);
+  MITK_INFO << "Number of observers: " << manager->GetNumberOfObservers();
+  //add multiple objects to the data storage => multiple observers should be created
+  mitk::Image::Pointer image1 = mitk::IOUtil::LoadImageA("D:/prg/MITK-02-bin/CMakeExternals/Source/MITK-Data/Pic3D.nrrd");
+  mitk::DataNode::Pointer node1 = mitk::DataNode::New();
+  node1->SetData(image1);
+  mitk::Image::Pointer image2 = mitk::IOUtil::LoadImageA("D:/prg/MITK-02-bin/CMakeExternals/Source/MITK-Data/Pic3D.nrrd");
+  mitk::DataNode::Pointer node2 = mitk::DataNode::New();
+  node2->SetData(image2);
+  ds->Add(node1);
+  ds->Add(node2);
+  MITK_INFO << "Number of observers: " << manager->GetNumberOfObservers();
+  MITK_TEST_CONDITION_REQUIRED(manager->GetRelevantNodes()->size() == 2, "Test if nodes have been added");
+
+  ds->Remove(node1);
+  ds->Remove(node2);
+  //remove them
+  MITK_INFO << "Number of observers: " << manager->GetNumberOfObservers();
+  }
+
 };
 
 int mitkLevelWindowManagerTest(int, char* [])
 {
   MITK_TEST_BEGIN("mitkLevelWindowManager");
   mitkLevelWindowManagerTestClass::TestInstantiation();
   mitkLevelWindowManagerTestClass::TestSetGetDataStorage();
   mitkLevelWindowManagerTestClass::TestMethodsWithInvalidParameters();
+  mitkLevelWindowManagerTestClass::TestRemoveObserver();
 
   MITK_TEST_END();
 }