diff --git a/Plugins/org.mitk.gui.qt.properties/src/internal/QmitkPropertyItemSortFilterProxyModel.cpp b/Plugins/org.mitk.gui.qt.properties/src/internal/QmitkPropertyItemSortFilterProxyModel.cpp
index d0e96f4653..e927c371cf 100644
--- a/Plugins/org.mitk.gui.qt.properties/src/internal/QmitkPropertyItemSortFilterProxyModel.cpp
+++ b/Plugins/org.mitk.gui.qt.properties/src/internal/QmitkPropertyItemSortFilterProxyModel.cpp
@@ -1,58 +1,58 @@
 /*===================================================================
 
 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 "QmitkPropertyItemSortFilterProxyModel.h"
 
 QmitkPropertyItemSortFilterProxyModel::QmitkPropertyItemSortFilterProxyModel(QObject* parent)
   : QSortFilterProxyModel(parent)
 {
 }
 
 QmitkPropertyItemSortFilterProxyModel::~QmitkPropertyItemSortFilterProxyModel()
 {
 }
 
 bool QmitkPropertyItemSortFilterProxyModel::FilterAcceptsAnyChildRow(const QModelIndex& sourceParent) const
 {
   QString propertyName = this->sourceModel()->data(sourceParent).toString();
 
-  if (propertyName.contains(filterRegExp()))
+  if (propertyName.contains(this->filterRegExp()))
     return true;
 
   if (this->sourceModel()->hasChildren(sourceParent))
   {
     for (int row = 0; row < this->sourceModel()->rowCount(sourceParent); ++row)
     {
       if(this->FilterAcceptsAnyChildRow(this->sourceModel()->index(row, 0, sourceParent)))
         return true;
     }
   }
 
   return false;
 }
 
 bool QmitkPropertyItemSortFilterProxyModel::filterAcceptsRow(int sourceRow, const QModelIndex& sourceParent) const
 {
   return this->FilterAcceptsAnyChildRow(this->sourceModel()->index(sourceRow, 0, sourceParent));
 }
 
 bool QmitkPropertyItemSortFilterProxyModel::lessThan(const QModelIndex& left, const QModelIndex& right) const
 {
   QString leftString = this->sourceModel()->data(left).toString();
   QString rightString = this->sourceModel()->data(right).toString();
 
   return leftString.compare(rightString, this->sortCaseSensitivity()) < 0;
 }
diff --git a/Plugins/org.mitk.gui.qt.properties/src/internal/QmitkPropertyTreeView.cpp b/Plugins/org.mitk.gui.qt.properties/src/internal/QmitkPropertyTreeView.cpp
index 2c4d42d0c4..a5274aff70 100644
--- a/Plugins/org.mitk.gui.qt.properties/src/internal/QmitkPropertyTreeView.cpp
+++ b/Plugins/org.mitk.gui.qt.properties/src/internal/QmitkPropertyTreeView.cpp
@@ -1,463 +1,451 @@
 /*===================================================================
 
 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 "mitkGetPropertyService.h"
 #include "QmitkAddNewPropertyDialog.h"
 #include "QmitkPropertiesPreferencePage.h"
 #include "QmitkPropertyItemDelegate.h"
 #include "QmitkPropertyItemModel.h"
 #include "QmitkPropertyItemSortFilterProxyModel.h"
 #include "QmitkPropertyTreeView.h"
 #include <berryIBerryPreferences.h>
 #include <mitkIPropertyAliases.h>
 #include <mitkIPropertyDescriptions.h>
 #include <mitkIPropertyPersistence.h>
 #include <QmitkRenderWindow.h>
 #include <QPainter>
 #include <memory>
 
 const std::string QmitkPropertyTreeView::VIEW_ID = "org.mitk.views.properties";
 
 QmitkPropertyTreeView::QmitkPropertyTreeView()
   : m_Parent(nullptr),
     m_PropertyNameChangedTag(0),
     m_PropertyAliases(nullptr),
     m_PropertyDescriptions(nullptr),
     m_PropertyPersistence(nullptr),
     m_ShowAliasesInDescription(true),
     m_ShowPersistenceInDescription(true),
     m_DeveloperMode(false),
     m_ProxyModel(nullptr),
     m_Model(nullptr),
     m_Delegate(nullptr),
     m_Renderer(nullptr)
 {
 }
 
 QmitkPropertyTreeView::~QmitkPropertyTreeView()
 {
 }
 
 void QmitkPropertyTreeView::CreateQtPartControl(QWidget* parent)
 {
   m_Parent = parent;
 
   m_Controls.setupUi(parent);
 
   m_Controls.propertyListComboBox->addItem("Data node: common");
 
   mitk::IRenderWindowPart* renderWindowPart = this->GetRenderWindowPart();
 
-  if (renderWindowPart != NULL)
+  if (renderWindowPart != nullptr)
   {
     QHash<QString, QmitkRenderWindow*> renderWindows = renderWindowPart->GetQmitkRenderWindows();
 
     Q_FOREACH(QString renderWindow, renderWindows.keys())
     {
       m_Controls.propertyListComboBox->addItem(QString("Data node: ") + renderWindow);
     }
   }
 
   m_Controls.propertyListComboBox->addItem("Base data");
 
   m_Controls.newButton->setEnabled(false);
 
   m_Controls.description->hide();
   m_Controls.propertyListLabel->hide();
   m_Controls.propertyListComboBox->hide();
   m_Controls.newButton->hide();
 
   m_ProxyModel = new QmitkPropertyItemSortFilterProxyModel(m_Controls.treeView);
   m_Model = new QmitkPropertyItemModel(m_ProxyModel);
 
   m_ProxyModel->setSourceModel(m_Model);
   m_ProxyModel->setFilterCaseSensitivity(Qt::CaseInsensitive);
   m_ProxyModel->setSortCaseSensitivity(Qt::CaseInsensitive);
   m_ProxyModel->setDynamicSortFilter(true);
 
   m_Delegate = new QmitkPropertyItemDelegate(m_Controls.treeView);
 
-#if QT_VERSION >= QT_VERSION_CHECK(5, 2, 0)
   m_Controls.filterLineEdit->setClearButtonEnabled(true);
-#endif
 
   m_Controls.treeView->setItemDelegateForColumn(1, m_Delegate);
   m_Controls.treeView->setModel(m_ProxyModel);
   m_Controls.treeView->setColumnWidth(0, 160);
   m_Controls.treeView->sortByColumn(0, Qt::AscendingOrder);
   m_Controls.treeView->setSelectionBehavior(QAbstractItemView::SelectRows);
   m_Controls.treeView->setSelectionMode(QAbstractItemView::SingleSelection);
   m_Controls.treeView->setEditTriggers(QAbstractItemView::SelectedClicked | QAbstractItemView::DoubleClicked);
 
   connect(m_Controls.filterLineEdit, SIGNAL(textChanged(const QString&)), this, SLOT(OnFilterTextChanged(const QString&)));
   connect(m_Controls.propertyListComboBox, SIGNAL(currentIndexChanged(int)), this, SLOT(OnPropertyListChanged(int)));
   connect(m_Controls.newButton, SIGNAL(clicked()), this, SLOT(OnAddNewProperty()));
   connect(m_Controls.treeView->selectionModel(), SIGNAL(currentRowChanged(const QModelIndex&, const QModelIndex&)), this, SLOT(OnCurrentRowChanged(const QModelIndex&, const QModelIndex&)));
   connect(m_Model, SIGNAL(modelReset()), this, SLOT(OnModelReset()));
 }
 
 QString QmitkPropertyTreeView::GetPropertyNameOrAlias(const QModelIndex& index)
 {
   QString propertyName;
 
   if (index.isValid())
   {
     QModelIndex current = index;
 
     while (current.isValid())
     {
       QString name = m_ProxyModel->data(m_ProxyModel->index(current.row(), 0, current.parent())).toString();
 
       propertyName.prepend(propertyName.isEmpty()
         ? name
         : name.append('.'));
 
       current = current.parent();
     }
   }
 
   return propertyName;
 }
 
 void QmitkPropertyTreeView::OnCurrentRowChanged(const QModelIndex& current, const QModelIndex&)
 {
   if (m_PropertyDescriptions != nullptr && current.isValid())
   {
     QString name = this->GetPropertyNameOrAlias(current);
 
     if (!name.isEmpty())
     {
       QString alias;
       bool isTrueName = true;
 
       if (m_PropertyAliases != nullptr)
       {
         std::string trueName = m_PropertyAliases->GetPropertyName(name.toStdString());
 
         if (trueName.empty() && !m_SelectionClassName.empty())
           trueName = m_PropertyAliases->GetPropertyName(name.toStdString(), m_SelectionClassName);
 
         if (!trueName.empty())
         {
           alias = name;
           name = QString::fromStdString(trueName);
           isTrueName = false;
         }
       }
 
       QString description = QString::fromStdString(m_PropertyDescriptions->GetDescription(name.toStdString()));
       std::vector<std::string> aliases;
 
       if (!isTrueName && m_PropertyAliases != nullptr)
       {
         aliases = m_PropertyAliases->GetAliases(name.toStdString(), m_SelectionClassName);
 
         if (aliases.empty() && !m_SelectionClassName.empty())
           aliases = m_PropertyAliases->GetAliases(name.toStdString());
       }
 
       bool isPersistent = false;
-      // QString persistenceKey;
 
       if (m_PropertyPersistence != nullptr)
-      {
         isPersistent = m_PropertyPersistence->HasInfo(name.toStdString());
 
-        /*if (isPersistent)
-        {
-          persistenceKey = QString::fromStdString(m_PropertyPersistence->GetInfo(name.toStdString())->GetKey());
-
-          if (persistenceKey.isEmpty())
-            persistenceKey = name;
-        }*/
-      }
-
       if (!description.isEmpty() || !aliases.empty() || isPersistent)
       {
         QString customizedDescription;
 
         if (m_ShowAliasesInDescription && !aliases.empty())
         {
           customizedDescription = "<h3 style=\"margin-bottom:0\">" + name + "</h3>";
 
           std::size_t numAliases = aliases.size();
           std::size_t lastAlias = numAliases - 1;
 
           for (std::size_t i = 0; i < numAliases; ++i)
           {
             customizedDescription += i != lastAlias
               ? "<h5 style=\"margin-top:0;margin-bottom:0\">"
               : "<h5 style=\"margin-top:0;margin-bottom:10px\">";
 
             customizedDescription += QString::fromStdString(aliases[i]) + "</h5>";
           }
         }
         else
         {
           customizedDescription = "<h3 style=\"margin-bottom:10px\">" + name + "</h3>";
         }
 
         if (!description.isEmpty())
           customizedDescription += "<p>" + description + "</p>";
 
         if (!aliases.empty() || isPersistent)
         {
           customizedDescription += "<div align=\"right\">";
 
           if (!aliases.empty())
           {
             customizedDescription += aliases.size() > 1
               ? "<img height=\"32\" src=\":/org_mitk_icons/icons/awesome/scalable/tags.svg\"/>"
               : "<img height=\"32\" src=\":/org_mitk_icons/icons/awesome/scalable/tag.svg\"/>";
           }
 
           if (isPersistent)
             customizedDescription += "<img height=\"32\" src=\":/org_mitk_icons/icons/awesome/scalable/actions/document-save.svg\"/>";
 
           customizedDescription += "</div>";
         }
 
         m_Controls.description->setText(customizedDescription);
         m_Controls.description->show();
 
         return;
       }
     }
   }
 
   m_Controls.description->hide();
 }
 
 void QmitkPropertyTreeView::OnFilterTextChanged(const QString& filter)
 {
   m_ProxyModel->setFilterWildcard(filter);
 
   if (filter.isEmpty())
     m_Controls.treeView->collapseAll();
   else
     m_Controls.treeView->expandAll();
 }
 
 void QmitkPropertyTreeView::OnModelReset()
 {
   m_Controls.description->hide();
 }
 
 void QmitkPropertyTreeView::OnPreferencesChanged(const berry::IBerryPreferences* preferences)
 {
   bool showAliases = preferences->GetBool(QmitkPropertiesPreferencePage::SHOW_ALIASES, true);
   bool showDescriptions = preferences->GetBool(QmitkPropertiesPreferencePage::SHOW_DESCRIPTIONS, true);
   bool showAliasesInDescription = preferences->GetBool(QmitkPropertiesPreferencePage::SHOW_ALIASES_IN_DESCRIPTION, true);
   bool showPersistenceInDescription = preferences->GetBool(QmitkPropertiesPreferencePage::SHOW_PERSISTENCE_IN_DESCRIPTION, true);
   bool developerMode = preferences->GetBool(QmitkPropertiesPreferencePage::DEVELOPER_MODE, false);
   bool filterProperties = preferences->GetBool(QmitkPropertiesPreferencePage::FILTER_PROPERTIES, true);
+
   m_Model->SetFilterProperties(filterProperties);
   m_Model->SetShowAliases(showAliases);
 
-  bool updateAliases = showAliases != (m_PropertyAliases != NULL);
-  bool updateDescriptions = showDescriptions != (m_PropertyDescriptions != NULL);
+  bool updateAliases = showAliases != (m_PropertyAliases != nullptr);
+  bool updateDescriptions = showDescriptions != (m_PropertyDescriptions != nullptr);
   bool updateAliasesInDescription = showAliasesInDescription != m_ShowAliasesInDescription;
   bool updatePersistenceInDescription = showPersistenceInDescription != m_ShowPersistenceInDescription;
   bool updateDeveloperMode = developerMode != m_DeveloperMode;
 
   if (updateAliases)
     m_PropertyAliases = showAliases
       ? mitk::GetPropertyService<mitk::IPropertyAliases>()
       : nullptr;
 
   if (updateDescriptions)
     m_PropertyDescriptions = showDescriptions
       ? mitk::GetPropertyService<mitk::IPropertyDescriptions>()
       : nullptr;
 
   if (showPersistenceInDescription)
     m_PropertyPersistence = mitk::GetPropertyService<mitk::IPropertyPersistence>();
 
   if (updateAliasesInDescription)
     m_ShowAliasesInDescription = showAliasesInDescription;
 
   if (updatePersistenceInDescription)
     m_ShowPersistenceInDescription = showPersistenceInDescription;
 
   if (updateDescriptions || updateAliasesInDescription || updatePersistenceInDescription)
   {
     QModelIndexList selection = m_Controls.treeView->selectionModel()->selectedRows();
 
     if (!selection.isEmpty())
       this->OnCurrentRowChanged(selection[0], selection[0]);
   }
 
   if (updateDeveloperMode)
   {
     m_DeveloperMode = developerMode;
 
     if (!developerMode)
       m_Controls.propertyListComboBox->setCurrentIndex(0);
 
     m_Controls.propertyListLabel->setVisible(developerMode);
     m_Controls.propertyListComboBox->setVisible(developerMode);
     m_Controls.newButton->setVisible(developerMode);
   }
 
   m_Model->OnPreferencesChanged();
 }
 
 void QmitkPropertyTreeView::OnPropertyNameChanged(const itk::EventObject&)
 {
   mitk::PropertyList* propertyList = m_Model->GetPropertyList();
 
-  if (propertyList != NULL)
+  if (propertyList != nullptr)
   {
     mitk::BaseProperty* nameProperty = propertyList->GetProperty("name");
 
-    if (nameProperty != NULL)
+    if (nameProperty != nullptr)
     {
       QString partName = "Properties (";
       partName.append(QString::fromStdString(nameProperty->GetValueAsString())).append(')');
       this->SetPartName(partName);
     }
   }
 }
 
 void QmitkPropertyTreeView::OnSelectionChanged(berry::IWorkbenchPart::Pointer, const QList<mitk::DataNode::Pointer>& nodes)
 {
   mitk::PropertyList* propertyList = m_Model->GetPropertyList();
 
-  if (propertyList != NULL)
+  if (propertyList != nullptr)
   {
     mitk::BaseProperty* nameProperty = propertyList->GetProperty("name");
 
-    if (nameProperty != NULL)
+    if (nameProperty != nullptr)
       nameProperty->RemoveObserver(m_PropertyNameChangedTag);
 
     m_PropertyNameChangedTag = 0;
   }
 
   if (nodes.empty() || nodes.front().IsNull())
   {
-    m_SelectedNode = NULL;
+    m_SelectedNode = nullptr;
 
     this->SetPartName("Properties");
-    m_Model->SetPropertyList(NULL);
-    m_Delegate->SetPropertyList(NULL);
+    m_Model->SetPropertyList(nullptr);
+    m_Delegate->SetPropertyList(nullptr);
 
     m_Controls.newButton->setEnabled(false);
   }
   else
   {
     m_SelectedNode = nodes.front();
 
-    QString selectionClassName = m_SelectedNode->GetData() != NULL
+    QString selectionClassName = m_SelectedNode->GetData() != nullptr
       ? m_SelectedNode->GetData()->GetNameOfClass()
       : "";
 
     m_SelectionClassName = selectionClassName.toStdString();
 
     mitk::PropertyList::Pointer propertyList;
 
-    if (m_Renderer == NULL && m_Controls.propertyListComboBox->currentText() == "Base data")
+    if (m_Renderer == nullptr && m_Controls.propertyListComboBox->currentText() == "Base data")
     {
-      propertyList = m_SelectedNode->GetData() != NULL
+      propertyList = m_SelectedNode->GetData() != nullptr
         ? m_SelectedNode->GetData()->GetPropertyList()
-        : NULL;
+        : nullptr;
     }
     else
     {
       propertyList = m_SelectedNode->GetPropertyList(m_Renderer);
     }
 
     m_Model->SetPropertyList(propertyList, selectionClassName);
     m_Delegate->SetPropertyList(propertyList);
 
     OnPropertyNameChanged(itk::ModifiedEvent());
 
     mitk::BaseProperty* nameProperty = m_SelectedNode->GetProperty("name");
 
-    if (nameProperty != NULL)
+    if (nameProperty != nullptr)
     {
       itk::ReceptorMemberCommand<QmitkPropertyTreeView>::Pointer command = itk::ReceptorMemberCommand<QmitkPropertyTreeView>::New();
       command->SetCallbackFunction(this, &QmitkPropertyTreeView::OnPropertyNameChanged);
       m_PropertyNameChangedTag = nameProperty->AddObserver(itk::ModifiedEvent(), command);
     }
 
     m_Controls.newButton->setEnabled(true);
   }
 
   if (!m_ProxyModel->filterRegExp().isEmpty())
     m_Controls.treeView->expandAll();
 }
 
 void QmitkPropertyTreeView::SetFocus()
 {
   m_Controls.filterLineEdit->setFocus();
 }
 
 void QmitkPropertyTreeView::RenderWindowPartActivated(mitk::IRenderWindowPart* /*renderWindowPart*/)
 {
   if (m_Controls.propertyListComboBox->count() == 2)
   {
     QHash<QString, QmitkRenderWindow*> renderWindows = this->GetRenderWindowPart()->GetQmitkRenderWindows();
 
     Q_FOREACH(QString renderWindow, renderWindows.keys())
     {
       m_Controls.propertyListComboBox->insertItem(m_Controls.propertyListComboBox->count() - 1, QString("Data node: ") + renderWindow);
     }
   }
 }
 
 void QmitkPropertyTreeView::RenderWindowPartDeactivated(mitk::IRenderWindowPart*)
 {
   if (m_Controls.propertyListComboBox->count() > 2)
   {
     m_Controls.propertyListComboBox->clear();
     m_Controls.propertyListComboBox->addItem("Data node: common");
     m_Controls.propertyListComboBox->addItem("Base data");
   }
 }
 
 void QmitkPropertyTreeView::OnPropertyListChanged(int index)
 {
   if (index == -1)
     return;
 
   QString renderer = m_Controls.propertyListComboBox->itemText(index);
 
   if (renderer.startsWith("Data node: "))
     renderer = QString::fromStdString(renderer.toStdString().substr(11));
 
   m_Renderer = renderer != "common" && renderer != "Base data"
     ? this->GetRenderWindowPart()->GetQmitkRenderWindow(renderer)->GetRenderer()
-    : NULL;
+    : nullptr;
 
   QList<mitk::DataNode::Pointer> nodes;
 
   if (m_SelectedNode.IsNotNull())
     nodes << m_SelectedNode;
 
   berry::IWorkbenchPart::Pointer workbenchPart;
 
   this->OnSelectionChanged(workbenchPart, nodes);
 }
 
 void QmitkPropertyTreeView::OnAddNewProperty()
 {
   std::unique_ptr<QmitkAddNewPropertyDialog> dialog(m_Controls.propertyListComboBox->currentText() != "Base data"
       ? new QmitkAddNewPropertyDialog(m_SelectedNode, m_Renderer, m_Parent)
       : new QmitkAddNewPropertyDialog(m_SelectedNode->GetData()));
 
   if (dialog->exec() == QDialog::Accepted)
     this->m_Model->Update();
 }