diff --git a/src/plugins/coreplugin/find/highlightscrollbar.cpp b/src/plugins/coreplugin/find/highlightscrollbar.cpp
index 5c25984758a..7a7a9f13b00 100644
--- a/src/plugins/coreplugin/find/highlightscrollbar.cpp
+++ b/src/plugins/coreplugin/find/highlightscrollbar.cpp
@@ -33,8 +33,39 @@
 #include <QStyleOptionSlider>
 #include <QTimer>
 
-using namespace Core;
 using namespace Utils;
+namespace Core {
+
+class HighlightScrollBarOverlay : public QWidget
+{
+public:
+    HighlightScrollBarOverlay(HighlightScrollBar *scrollBar)
+        : QWidget(scrollBar)
+        , m_visibleRange(0.0)
+        , m_offset(0.0)
+        , m_cacheUpdateScheduled(false)
+        , m_scrollBar(scrollBar)
+    {}
+
+    void scheduleUpdate();
+    void updateCache();
+    void adjustPosition();
+
+    float m_visibleRange;
+    float m_offset;
+    QHash<Id, QSet<int> > m_highlights;
+    QHash<Id, Utils::Theme::Color> m_colors;
+    QHash<Id, HighlightScrollBar::Priority> m_priorities;
+
+    bool m_cacheUpdateScheduled;
+    QMap<int, Id> m_cache;
+
+protected:
+    void paintEvent(QPaintEvent *paintEvent) override;
+
+private:
+    HighlightScrollBar *m_scrollBar;
+};
 
 HighlightScrollBar::HighlightScrollBar(Qt::Orientation orientation, QWidget *parent)
     : QScrollBar(orientation, parent)
@@ -295,3 +326,5 @@ void HighlightScrollBarOverlay::paintEvent(QPaintEvent *paintEvent)
         }
     }
 }
+
+} // namespace Core
diff --git a/src/plugins/coreplugin/find/highlightscrollbar.h b/src/plugins/coreplugin/find/highlightscrollbar.h
index d049e9b49fc..505db157582 100644
--- a/src/plugins/coreplugin/find/highlightscrollbar.h
+++ b/src/plugins/coreplugin/find/highlightscrollbar.h
@@ -82,36 +82,4 @@ private:
     friend class HighlightScrollBarOverlay;
 };
 
-class HighlightScrollBarOverlay : public QWidget
-{
-    Q_OBJECT
-public:
-    HighlightScrollBarOverlay(HighlightScrollBar *scrollBar)
-        : QWidget(scrollBar)
-        , m_visibleRange(0.0)
-        , m_offset(0.0)
-        , m_cacheUpdateScheduled(false)
-        , m_scrollBar(scrollBar)
-    {}
-
-    void scheduleUpdate();
-    void updateCache();
-    void adjustPosition();
-
-    float m_visibleRange;
-    float m_offset;
-    QHash<Id, QSet<int> > m_highlights;
-    QHash<Id, Utils::Theme::Color> m_colors;
-    QHash<Id, HighlightScrollBar::Priority> m_priorities;
-
-    bool m_cacheUpdateScheduled;
-    QMap<int, Id> m_cache;
-
-protected:
-    void paintEvent(QPaintEvent *paintEvent) override;
-
-private:
-    HighlightScrollBar *m_scrollBar;
-};
-
 } // namespace Core