diff --git a/Modules/QtWidgets/QmitkDataStorageFilterProxyModel.cpp b/Modules/QtWidgets/QmitkDataStorageFilterProxyModel.cpp
index 2f2e387023..eb7ddefe06 100644
--- a/Modules/QtWidgets/QmitkDataStorageFilterProxyModel.cpp
+++ b/Modules/QtWidgets/QmitkDataStorageFilterProxyModel.cpp
@@ -1,85 +1,85 @@
 /*===================================================================
 
 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 <mitkStringProperty.h>
 #include <mitkNodePredicateFirstLevel.h>
 #include <mitkNodePredicateAnd.h>
 #include <mitkNodePredicateData.h>
 #include <mitkNodePredicateNot.h>
 #include <mitkNodePredicateOr.h>
 #include <mitkNodePredicateProperty.h>
 #include <mitkPlanarFigure.h>
 #include <mitkProperties.h>
 #include <mitkRenderingManager.h>
 
 #include "QmitkDataStorageFilterProxyModel.h"
 #include "QmitkDataStorageTreeModel.h"
 #include "QmitkNodeDescriptorManager.h"
 #include <QmitkEnums.h>
 #include <QmitkCustomVariants.h>
 
 #include <QIcon>
 #include <QMimeData>
 #include <QTextStream>
 
 #include <map>
 
 QmitkDataStorageFilterProxyModel::QmitkDataStorageFilterProxyModel(QObject* parent)
 : QSortFilterProxyModel(parent)
 {
 }
 
 QmitkDataStorageFilterProxyModel::~QmitkDataStorageFilterProxyModel()
 {
 }
 
 
 void QmitkDataStorageFilterProxyModel::AddFilterPredicate(mitk::NodePredicateBase::Pointer pred)
 {
     m_Predicates.insert(pred);
     this->invalidateFilter();
 }
 
 bool QmitkDataStorageFilterProxyModel::RemoveFilterPredicate(mitk::NodePredicateBase::Pointer pred)
 {
     bool removed = m_Predicates.erase(pred) != 0;
     if (removed) {
         this->invalidateFilter();
     }
     return removed;
 }
 
 bool QmitkDataStorageFilterProxyModel::HasFilterPredicate(mitk::NodePredicateBase::Pointer pred)
 {
     return m_Predicates.find(pred) != m_Predicates.end();
 }
 
 bool QmitkDataStorageFilterProxyModel::filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const
 {
     QmitkDataStorageTreeModel* model = dynamic_cast<QmitkDataStorageTreeModel*>(this->sourceModel());
     assert(model);
 
     QModelIndex index0 = sourceModel()->index(sourceRow, 0, sourceParent);
 
-    for (FilterPredicatesCollection::iterator iter = m_Predicates.begin(); iter != m_Predicates.end(); ++iter) {
+    for (FilterPredicatesCollection::const_iterator iter = m_Predicates.begin(); iter != m_Predicates.end(); ++iter) {
         if ((*iter)->CheckNode(model->GetNode(index0))) {
             return false;
         }
     }
 
     return true;
 }