diff --git a/src/widget_type.h b/src/widget_type.h
--- a/src/widget_type.h
+++ b/src/widget_type.h
@@ -293,11 +293,11 @@ public:
 	inline void SetDisabled(bool disabled);
 	inline bool IsDisabled() const;
 
-	/* virtual */ void FillNestedArray(NWidgetBase **array, uint length);
-	/* virtual */ NWidgetCore *GetWidgetFromPos(int x, int y);
-	/* virtual */ bool IsHighlighted() const;
-	/* virtual */ TextColour GetHighlightColour() const;
-	/* virtual */ void SetHighlighted(TextColour highlight_colour);
+	void FillNestedArray(NWidgetBase **array, uint length) override;
+	NWidgetCore *GetWidgetFromPos(int x, int y) override;
+	bool IsHighlighted() const override;
+	TextColour GetHighlightColour() const override;
+	void SetHighlighted(TextColour highlight_colour) override;
 
 	NWidgetDisplay disp_flags; ///< Flags that affect display and interaction with the widget.
 	Colours colour;            ///< Colour of this widget.
@@ -371,12 +371,12 @@ public:
 	~NWidgetContainer();
 
 	void Add(NWidgetBase *wid);
-	/* virtual */ void FillNestedArray(NWidgetBase **array, uint length);
+	void FillNestedArray(NWidgetBase **array, uint length) override;
 
 	/** Return whether the container is empty. */
 	inline bool IsEmpty() { return head == NULL; }
 
-	/* virtual */ NWidgetBase *GetWidgetOfType(WidgetType tp);
+	NWidgetBase *GetWidgetOfType(WidgetType tp) override;
 
 protected:
 	NWidgetBase *head; ///< Pointer to first widget in container.
@@ -408,12 +408,12 @@ public:
 
 	void SetIndex(int index);
 
-	void SetupSmallestSize(Window *w, bool init_array);
-	void AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool rtl);
-	/* virtual */ void FillNestedArray(NWidgetBase **array, uint length);
+	void SetupSmallestSize(Window *w, bool init_array) override;
+	void AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool rtl) override;
+	void FillNestedArray(NWidgetBase **array, uint length) override;
 
-	/* virtual */ void Draw(const Window *w);
-	/* virtual */ NWidgetCore *GetWidgetFromPos(int x, int y);
+	void Draw(const Window *w) override;
+	NWidgetCore *GetWidgetFromPos(int x, int y) override;
 
 	void SetDisplayedPlane(int plane);
 
@@ -437,8 +437,8 @@ public:
 
 	void SetPIP(uint8 pip_pre, uint8 pip_inter, uint8 pip_post);
 
-	/* virtual */ void Draw(const Window *w);
-	/* virtual */ NWidgetCore *GetWidgetFromPos(int x, int y);
+	void Draw(const Window *w) override;
+	NWidgetCore *GetWidgetFromPos(int x, int y) override;
 
 protected:
 	NWidContainerFlags flags; ///< Flags of the container.
@@ -500,12 +500,12 @@ public:
 	void SetCount(int count);
 	void SetScrollbar(Scrollbar *sb);
 
-	void SetupSmallestSize(Window *w, bool init_array);
-	void AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool rtl);
-	/* virtual */ void FillNestedArray(NWidgetBase **array, uint length);
+	void SetupSmallestSize(Window *w, bool init_array) override;
+	void AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool rtl) override;
+	void FillNestedArray(NWidgetBase **array, uint length) override;
 
-	/* virtual */ NWidgetCore *GetWidgetFromPos(int x, int y);
-	/* virtual */ void Draw(const Window *w);
+	NWidgetCore *GetWidgetFromPos(int x, int y) override;
+	void Draw(const Window *w) override;
 protected:
 	int index;      ///< If non-negative, index in the #Window::nested_array.
 	Colours colour; ///< Colour of this widget.
@@ -530,12 +530,12 @@ class NWidgetSpacer : public NWidgetResi
 public:
 	NWidgetSpacer(int length, int height);
 
-	void SetupSmallestSize(Window *w, bool init_array);
-	/* virtual */ void FillNestedArray(NWidgetBase **array, uint length);
+	void SetupSmallestSize(Window *w, bool init_array) override;
+	void FillNestedArray(NWidgetBase **array, uint length) override;
 
-	/* virtual */ void Draw(const Window *w);
-	/* virtual */ void SetDirty(const Window *w) const;
-	/* virtual */ NWidgetCore *GetWidgetFromPos(int x, int y);
+	void Draw(const Window *w) override;
+	void SetDirty(const Window *w) const override;
+	NWidgetCore *GetWidgetFromPos(int x, int y) override;
 };
 
 /**
@@ -550,14 +550,14 @@ public:
 	void Add(NWidgetBase *nwid);
 	void SetPIP(uint8 pip_pre, uint8 pip_inter, uint8 pip_post);
 
-	void SetupSmallestSize(Window *w, bool init_array);
-	void AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool rtl);
+	void SetupSmallestSize(Window *w, bool init_array) override;
+	void AssignSizePosition(SizingType sizing, uint x, uint y, uint given_width, uint given_height, bool rtl) override;
 
-	/* virtual */ void FillNestedArray(NWidgetBase **array, uint length);
+	void FillNestedArray(NWidgetBase **array, uint length) override;
 
-	/* virtual */ void Draw(const Window *w);
-	/* virtual */ NWidgetCore *GetWidgetFromPos(int x, int y);
-	/* virtual */ NWidgetBase *GetWidgetOfType(WidgetType tp);
+	void Draw(const Window *w) override;
+	NWidgetCore *GetWidgetFromPos(int x, int y) override;
+	NWidgetBase *GetWidgetOfType(WidgetType tp) override;
 
 private:
 	NWidgetPIPContainer *child; ///< Child widget.
@@ -576,8 +576,8 @@ class NWidgetViewport : public NWidgetCo
 public:
 	NWidgetViewport(int index);
 
-	/* virtual */ void SetupSmallestSize(Window *w, bool init_array);
-	/* virtual */ void Draw(const Window *w);
+	void SetupSmallestSize(Window *w, bool init_array) override;
+	void Draw(const Window *w) override;
 
 	void InitializeViewport(Window *w, uint32 follow_flags, ZoomLevel zoom);
 	void UpdateViewportCoordinates(Window *w);
@@ -751,8 +751,8 @@ class NWidgetScrollbar : public NWidgetC
 public:
 	NWidgetScrollbar(WidgetType tp, Colours colour, int index);
 
-	/* virtual */ void SetupSmallestSize(Window *w, bool init_array);
-	/* virtual */ void Draw(const Window *w);
+	void SetupSmallestSize(Window *w, bool init_array) override;
+	void Draw(const Window *w) override;
 
 	static void InvalidateDimensionCache();
 	static Dimension GetVerticalDimension();
@@ -771,8 +771,8 @@ class NWidgetLeaf : public NWidgetCore {
 public:
 	NWidgetLeaf(WidgetType tp, Colours colour, int index, uint32 data, StringID tip);
 
-	/* virtual */ void SetupSmallestSize(Window *w, bool init_array);
-	/* virtual */ void Draw(const Window *w);
+	void SetupSmallestSize(Window *w, bool init_array) override;
+	void Draw(const Window *w) override;
 
 	bool ButtonHit(const Point &pt);