diff --git a/src/depot_gui.cpp b/src/depot_gui.cpp
--- a/src/depot_gui.cpp
+++ b/src/depot_gui.cpp
@@ -258,7 +258,7 @@ struct DepotWindow : Window {
 	VehicleID vehicle_over; ///< Rail vehicle over which another one is dragged, \c INVALID_VEHICLE if none.
 	VehicleType type;
 	bool generate_list;
-	int hovered_widget; ///< Index of the widget being hovered during drag/drop. -1 if no drag is in progress.
+	WidgetID hovered_widget; ///< Index of the widget being hovered during drag/drop. -1 if no drag is in progress.
 	VehicleList vehicle_list;
 	VehicleList wagon_list;
 	uint unitnumber_digits;
@@ -363,7 +363,7 @@ struct DepotWindow : Window {
 		}
 	}
 
-	void DrawWidget(const Rect &r, int widget) const override
+	void DrawWidget(const Rect &r, WidgetID widget) const override
 	{
 		if (widget != WID_D_MATRIX) return;
 
@@ -421,7 +421,7 @@ struct DepotWindow : Window {
 		}
 	}
 
-	void SetStringParameters(int widget) const override
+	void SetStringParameters(WidgetID widget) const override
 	{
 		if (widget != WID_D_CAPTION) return;
 
@@ -653,7 +653,7 @@ struct DepotWindow : Window {
 		this->flag_size = maxdim(GetScaledSpriteSize(SPR_FLAG_VEH_STOPPED), GetScaledSpriteSize(SPR_FLAG_VEH_RUNNING));
 	}
 
-	void UpdateWidgetSize(int widget, Dimension *size, [[maybe_unused]] const Dimension &padding, [[maybe_unused]] Dimension *fill, [[maybe_unused]] Dimension *resize) override
+	void UpdateWidgetSize(WidgetID widget, Dimension *size, [[maybe_unused]] const Dimension &padding, [[maybe_unused]] Dimension *fill, [[maybe_unused]] Dimension *resize) override
 	{
 		switch (widget) {
 			case WID_D_MATRIX: {
@@ -757,7 +757,7 @@ struct DepotWindow : Window {
 		this->DrawWidgets();
 	}
 
-	void OnClick([[maybe_unused]] Point pt, int widget, [[maybe_unused]] int click_count) override
+	void OnClick([[maybe_unused]] Point pt, WidgetID widget, [[maybe_unused]] int click_count) override
 	{
 		switch (widget) {
 			case WID_D_MATRIX: // List
@@ -839,7 +839,7 @@ struct DepotWindow : Window {
 		Command<CMD_RENAME_DEPOT>::Post(STR_ERROR_CAN_T_RENAME_DEPOT, this->GetDepotIndex(), str);
 	}
 
-	bool OnRightClick([[maybe_unused]] Point pt, int widget) override
+	bool OnRightClick([[maybe_unused]] Point pt, WidgetID widget) override
 	{
 		if (widget != WID_D_MATRIX) return false;
 
@@ -974,7 +974,7 @@ struct DepotWindow : Window {
 		}
 	}
 
-	void OnMouseDrag(Point pt, int widget) override
+	void OnMouseDrag(Point pt, WidgetID widget) override
 	{
 		if (this->sel == INVALID_VEHICLE) return;
 		if (widget != this->hovered_widget) {
@@ -1025,7 +1025,7 @@ struct DepotWindow : Window {
 		this->SetWidgetDirty(widget);
 	}
 
-	void OnDragDrop(Point pt, int widget) override
+	void OnDragDrop(Point pt, WidgetID widget) override
 	{
 		switch (widget) {
 			case WID_D_MATRIX: {