diff --git a/src/object_gui.cpp b/src/object_gui.cpp
--- a/src/object_gui.cpp
+++ b/src/object_gui.cpp
@@ -222,7 +222,7 @@ public:
 		this->object_margin = ScaleGUITrad(4);
 	}
 
-	void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize) override
+	void UpdateWidgetSize(int widget, Dimension *size, [[maybe_unused]] const Dimension &padding, [[maybe_unused]] Dimension *fill, [[maybe_unused]] Dimension *resize) override
 	{
 		switch (widget) {
 			case WID_BO_CLASS_LIST: {
@@ -490,7 +490,7 @@ public:
 		this->SetDirty();
 	}
 
-	void OnInvalidateData(int data = 0, bool gui_scope = true) override
+	void OnInvalidateData([[maybe_unused]] int data = 0, [[maybe_unused]] bool gui_scope = true) override
 	{
 		if (!gui_scope) return;
 
@@ -502,7 +502,7 @@ public:
 		this->vscroll->SetCapacityFromWidget(this, WID_BO_CLASS_LIST);
 	}
 
-	void OnClick(Point pt, int widget, int click_count) override
+	void OnClick([[maybe_unused]] Point pt, int widget, [[maybe_unused]] int click_count) override
 	{
 		switch (GB(widget, 0, 16)) {
 			case WID_BO_CLASS_LIST: {
@@ -530,7 +530,7 @@ public:
 		}
 	}
 
-	void OnPlaceObject(Point pt, TileIndex tile) override
+	void OnPlaceObject([[maybe_unused]] Point pt, TileIndex tile) override
 	{
 		const ObjectSpec *spec = ObjectClass::Get(_selected_object_class)->GetSpec(_selected_object_index);
 
@@ -541,12 +541,12 @@ public:
 		}
 	}
 
-	void OnPlaceDrag(ViewportPlaceMethod select_method, ViewportDragDropSelectionProcess select_proc, Point pt) override
+	void OnPlaceDrag(ViewportPlaceMethod select_method, [[maybe_unused]] ViewportDragDropSelectionProcess select_proc, [[maybe_unused]] Point pt) override
 	{
 		VpSelectTilesWithMethod(pt.x, pt.y, select_method);
 	}
 
-	void OnPlaceMouseUp(ViewportPlaceMethod select_method, ViewportDragDropSelectionProcess select_proc, Point pt, TileIndex start_tile, TileIndex end_tile) override
+	void OnPlaceMouseUp([[maybe_unused]] ViewportPlaceMethod select_method, [[maybe_unused]] ViewportDragDropSelectionProcess select_proc, [[maybe_unused]] Point pt, TileIndex start_tile, TileIndex end_tile) override
 	{
 		if (pt.x == -1) return;