diff --git a/src/subsidy_gui.cpp b/src/subsidy_gui.cpp
--- a/src/subsidy_gui.cpp
+++ b/src/subsidy_gui.cpp
@@ -38,7 +38,7 @@ struct SubsidyListWindow : Window {
 		this->OnInvalidateData(0);
 	}
 
-	virtual void OnClick(Point pt, int widget, int click_count)
+	void OnClick(Point pt, int widget, int click_count) override
 	{
 		if (widget != WID_SUL_PANEL) return;
 
@@ -129,7 +129,7 @@ struct SubsidyListWindow : Window {
 		return 3 + num_awarded + num_not_awarded;
 	}
 
-	virtual void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize)
+	void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize) override
 	{
 		if (widget != WID_SUL_PANEL) return;
 		Dimension d = maxdim(GetStringBoundingBox(STR_SUBSIDIES_OFFERED_TITLE), GetStringBoundingBox(STR_SUBSIDIES_SUBSIDISED_TITLE));
@@ -142,7 +142,7 @@ struct SubsidyListWindow : Window {
 		*size = maxdim(*size, d);
 	}
 
-	virtual void DrawWidget(const Rect &r, int widget) const
+	void DrawWidget(const Rect &r, int widget) const override
 	{
 		if (widget != WID_SUL_PANEL) return;
 
@@ -207,7 +207,7 @@ struct SubsidyListWindow : Window {
 		}
 	}
 
-	virtual void OnResize()
+	void OnResize() override
 	{
 		this->vscroll->SetCapacityFromWidget(this, WID_SUL_PANEL);
 	}
@@ -217,7 +217,7 @@ struct SubsidyListWindow : Window {
 	 * @param data Information about the changed data.
 	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
 	 */
-	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
+	void OnInvalidateData(int data = 0, bool gui_scope = true) override
 	{
 		if (!gui_scope) return;
 		this->vscroll->SetCount(this->CountLines());