Hide build river button when disabled instead of visually disabling it

src/dock_gui.cpp

@@ -96,10 +96,13 @@ struct BuildDocksToolbarWindow : Window {
 	BuildDocksToolbarWindow(WindowDesc *desc, WindowNumber window_number) : Window(desc)
 	{
 		this->last_clicked_widget = WID_DT_INVALID;
-		this->InitNested(window_number);
+		this->CreateNestedTree();
+		if (_game_mode != GM_EDITOR) {
+			this->GetWidget<NWidgetStacked>(WID_DT_RIVER_SEL)->SetDisplayedPlane(_settings_game.construction.enable_build_river ? 0 : SZSP_NONE);
+		}
+		this->FinishInitNested(window_number);
 		this->OnInvalidateData();
 		if (_settings_client.gui.link_terraform_toolbar) ShowTerraformToolbar(this);
-		SetWidgetDisabledState(WID_DT_RIVER, _game_mode != GM_EDITOR && !_settings_game.construction.enable_build_river);
 	}
 
 	~BuildDocksToolbarWindow()
@@ -336,7 +339,9 @@ static const NWidgetPart _nested_build_docks_toolbar_widgets[] = {
 		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_DT_DEPOT), SetMinimalSize(22, 22), SetFill(0, 1), SetDataTip(SPR_IMG_SHIP_DEPOT, STR_WATERWAYS_TOOLBAR_BUILD_DEPOT_TOOLTIP),
 		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_DT_STATION), SetMinimalSize(22, 22), SetFill(0, 1), SetDataTip(SPR_IMG_SHIP_DOCK, STR_WATERWAYS_TOOLBAR_BUILD_DOCK_TOOLTIP),
 		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_DT_BUOY), SetMinimalSize(22, 22), SetFill(0, 1), SetDataTip(SPR_IMG_BUOY, STR_WATERWAYS_TOOLBAR_BUOY_TOOLTIP),
-		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_DT_RIVER), SetMinimalSize(22, 22), SetFill(0, 1), SetDataTip(SPR_IMG_BUILD_RIVER, STR_WATERWAYS_TOOLBAR_CREATE_RIVER_IN_GAME_TOOLTIP),
+		NWidget(NWID_SELECTION, INVALID_COLOUR, WID_DT_RIVER_SEL),
+			NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_DT_RIVER), SetMinimalSize(22, 22), SetFill(0, 1), SetDataTip(SPR_IMG_BUILD_RIVER, STR_WATERWAYS_TOOLBAR_CREATE_RIVER_IN_GAME_TOOLTIP),
+		EndContainer(),
 		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_DT_BUILD_AQUEDUCT), SetMinimalSize(23, 22), SetFill(0, 1), SetDataTip(SPR_IMG_AQUEDUCT, STR_WATERWAYS_TOOLBAR_BUILD_AQUEDUCT_TOOLTIP),
 	EndContainer(),
 };

src/widgets/dock_widget.h

@@ -27,6 +27,7 @@ enum DockToolbarWidgets {
 	WID_DT_BUOY,           ///< Build buoy button.
 	WID_DT_RIVER,          ///< Build river button (in scenario editor).
 	WID_DT_BUILD_AQUEDUCT, ///< Build aqueduct button.
+	WID_DT_RIVER_SEL,      ///< Build river button selector.
 
 	WID_DT_INVALID,        ///< Used to initialize a variable.
 };