diff --git a/GUI/Views/widgetbox/SampleToolBoxTreeWidget.cpp b/GUI/Views/widgetbox/SampleToolBoxTreeWidget.cpp
index 6bc4ba48905c9749a1aafb3aef3f312b78c78024..cc0ae4a3417d7909ed0cdf24d78c2e443d52d5d5 100644
--- a/GUI/Views/widgetbox/SampleToolBoxTreeWidget.cpp
+++ b/GUI/Views/widgetbox/SampleToolBoxTreeWidget.cpp
@@ -43,15 +43,14 @@ SampleToolBoxTreeWidget::SampleToolBoxTreeWidget(QWidget* parent)
 
     setItemDelegate(new qdesigner_internal::SheetDelegate(this, this));
 
-    connect(this, SIGNAL(itemPressed(QTreeWidgetItem*, int)), this,
-            SLOT(handleMousePress(QTreeWidgetItem*)));
+    connect(this, &QTreeWidget::itemPressed, this, &SampleToolBoxTreeWidget::handleMousePress);
 }
 
-SampleToolBoxGroupView* SampleToolBoxTreeWidget::categoryViewAt(int idx) const
+SampleToolBoxGroupView* SampleToolBoxTreeWidget::groupViewAt(int idx) const
 {
     SampleToolBoxGroupView* rc = nullptr;
-    if (QTreeWidgetItem* cat_item = topLevelItem(idx))
-        if (QTreeWidgetItem* embedItem = cat_item->child(0))
+    if (QTreeWidgetItem* groupItem = topLevelItem(idx))
+        if (QTreeWidgetItem* embedItem = groupItem->child(0))
             rc = qobject_cast<SampleToolBoxGroupView*>(itemWidget(embedItem, 0));
     ASSERT(rc);
     return rc;
@@ -75,22 +74,20 @@ void SampleToolBoxTreeWidget::handleMousePress(QTreeWidgetItem* item)
     }
 }
 
-SampleToolBoxGroupView* SampleToolBoxTreeWidget::addCategoryView(QTreeWidgetItem* parent,
-                                                                 bool iconMode)
+void SampleToolBoxTreeWidget::addGroupView(QTreeWidgetItem* parent, bool iconMode)
 {
     QTreeWidgetItem* embed_item = new QTreeWidgetItem(parent);
     embed_item->setFlags(Qt::ItemIsEnabled);
-    SampleToolBoxGroupView* categoryView = new SampleToolBoxGroupView(this);
-    categoryView->setViewMode(iconMode ? QListView::IconMode : QListView::ListMode);
-    connect(categoryView, SIGNAL(pressed(QString, QString, QPoint)), this,
+    SampleToolBoxGroupView* view = new SampleToolBoxGroupView(this);
+    view->setViewMode(iconMode ? QListView::IconMode : QListView::ListMode);
+    connect(view, SIGNAL(pressed(QString, QString, QPoint)), this,
             SIGNAL(pressed(QString, QString, QPoint)));
-    setItemWidget(embed_item, 0, categoryView);
-    return categoryView;
+    setItemWidget(embed_item, 0, view);
 }
 
-void SampleToolBoxTreeWidget::adjustSubListSize(QTreeWidgetItem* cat_item)
+void SampleToolBoxTreeWidget::adjustSubListSize(QTreeWidgetItem* groupItem)
 {
-    QTreeWidgetItem* embedItem = cat_item->child(0);
+    QTreeWidgetItem* embedItem = groupItem->child(0);
     if (embedItem == nullptr)
         return;
 
@@ -121,9 +118,9 @@ void SampleToolBoxTreeWidget::updateViewMode()
         for (int i = numTopLevels - 1; i >= 0; --i) {
             const QListView::ViewMode viewMode =
                 m_iconMode ? QListView::IconMode : QListView::ListMode;
-            SampleToolBoxGroupView* categoryView = categoryViewAt(i);
-            if (viewMode != categoryView->viewMode()) {
-                categoryView->setViewMode(viewMode);
+            SampleToolBoxGroupView* view = groupViewAt(i);
+            if (viewMode != view->viewMode()) {
+                view->setViewMode(viewMode);
                 adjustSubListSize(topLevelItem(i));
             }
         }
@@ -160,8 +157,8 @@ void SampleToolBoxTreeWidget::contextMenuEvent(QContextMenuEvent* e)
         iconModeAction->setChecked(true);
     else
         listModeAction->setChecked(true);
-    connect(listModeAction, SIGNAL(triggered()), SLOT(slotListMode()));
-    connect(iconModeAction, SIGNAL(triggered()), SLOT(slotIconMode()));
+    connect(listModeAction, &QAction::triggered, this, &SampleToolBoxTreeWidget::slotListMode);
+    connect(iconModeAction, &QAction::triggered, this, &SampleToolBoxTreeWidget::slotIconMode);
 
     e->accept();
     menu.exec(mapToGlobal(e->pos()));
@@ -175,19 +172,19 @@ void SampleToolBoxTreeWidget::filter(const QString& f)
     bool changed = false;
     for (int i = 0; i < numTopLevels; i++) {
         QTreeWidgetItem* tl = topLevelItem(i);
-        SampleToolBoxGroupView* categoryView = categoryViewAt(i);
-        // Anything changed? -> Enable the category
-        const int oldCount = categoryView->count(SampleToolBoxGroupView::FILTERED);
-        categoryView->filter(re);
-        const int newCount = categoryView->count(SampleToolBoxGroupView::FILTERED);
+        SampleToolBoxGroupView* groupView = groupViewAt(i);
+        // Anything changed? -> Enable the group
+        const int oldCount = groupView->count(SampleToolBoxGroupView::FILTERED);
+        groupView->filter(re);
+        const int newCount = groupView->count(SampleToolBoxGroupView::FILTERED);
         if (oldCount != newCount) {
             changed = true;
-            const bool categoryEnabled = newCount > 0 || empty;
-            if (categoryEnabled) {
-                categoryView->adjustSize();
+            const bool groupEnabled = newCount > 0 || empty;
+            if (groupEnabled) {
+                groupView->adjustSize();
                 adjustSubListSize(tl);
             }
-            setRowHidden(i, QModelIndex(), !categoryEnabled);
+            setRowHidden(i, QModelIndex(), !groupEnabled);
         }
     }
     if (changed)
@@ -196,27 +193,23 @@ void SampleToolBoxTreeWidget::filter(const QString& f)
 
 void SampleToolBoxTreeWidget::addGroup(const QString& title)
 {
-    QTreeWidgetItem* cat_item = new QTreeWidgetItem();
-    cat_item->setText(0, title);
-    addTopLevelItem(cat_item);
+    QTreeWidgetItem* groupItem = new QTreeWidgetItem();
+    groupItem->setText(0, title);
+    addTopLevelItem(groupItem);
 #if QT_VERSION >= QT_VERSION_CHECK(5, 13, 0)
-    cat_item->setExpanded(true);
+    groupItem->setExpanded(true);
 #else
-    setItemExpanded(cat_item, true);
+    setItemExpanded(groupItem, true);
 #endif
 
-    addCategoryView(cat_item, m_iconMode);
-    adjustSubListSize(cat_item);
+    addGroupView(groupItem, m_iconMode);
+    adjustSubListSize(groupItem);
 }
 
 void SampleToolBoxTreeWidget::addEntry(const QString& title, const QIcon& icon,
                                        const QString& className, const QString& tooltip)
 {
-    const auto cat_idx = topLevelItemCount() - 1;
-
-    QTreeWidgetItem* cat_item = topLevelItem(cat_idx);
-    SampleToolBoxGroupView* categoryView = categoryViewAt(cat_idx);
-
-    categoryView->addEntry(title, icon, className, tooltip);
-    adjustSubListSize(cat_item);
+    const auto groupIndex = topLevelItemCount() - 1;
+    groupViewAt(groupIndex)->addEntry(title, icon, className, tooltip);
+    adjustSubListSize(topLevelItem(groupIndex));
 }
diff --git a/GUI/Views/widgetbox/SampleToolBoxTreeWidget.h b/GUI/Views/widgetbox/SampleToolBoxTreeWidget.h
index edb1a2aee4dee7edbde4f66a05a2b223dc4454fb..683a8771a6b7763abd6b9edb40e4862b9cbffbb4 100644
--- a/GUI/Views/widgetbox/SampleToolBoxTreeWidget.h
+++ b/GUI/Views/widgetbox/SampleToolBoxTreeWidget.h
@@ -34,24 +34,22 @@ public:
     void addEntry(const QString& title, const QIcon& icon, const QString& className,
                   const QString& tooltip);
 
+    void filter(const QString&);
+
 signals:
     void pressed(const QString name, const QString dom_xml, const QPoint& global_mouse_pos);
 
-public slots:
-    void filter(const QString&);
-
 protected:
-    virtual void contextMenuEvent(QContextMenuEvent* e);
-    virtual void resizeEvent(QResizeEvent* e);
+    virtual void contextMenuEvent(QContextMenuEvent* e) override;
+    virtual void resizeEvent(QResizeEvent* e) override;
 
-private slots:
+private:
     void handleMousePress(QTreeWidgetItem* item);
     void slotListMode();
     void slotIconMode();
 
-private:
-    SampleToolBoxGroupView* addCategoryView(QTreeWidgetItem* parent, bool iconMode);
-    SampleToolBoxGroupView* categoryViewAt(int idx) const;
+    void addGroupView(QTreeWidgetItem* parent, bool iconMode);
+    SampleToolBoxGroupView* groupViewAt(int idx) const;
     void adjustSubListSize(QTreeWidgetItem* cat_item);
     void updateViewMode();