Cleanup: Remove redundant WWT_PANEL SetDataTips.

WWT_PANEL defaults to 0x0 data and no tooltip, so no need to declare
the same in the widget tree.

src/rail_gui.cpp

@@ -813,7 +813,7 @@ static const NWidgetPart _nested_build_rail_widgets[] = {
 		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_RAT_AUTORAIL),
 						SetFill(0, 1), SetMinimalSize(22, 22), SetDataTip(SPR_IMG_AUTORAIL, STR_RAIL_TOOLBAR_TOOLTIP_BUILD_AUTORAIL),
 
-		NWidget(WWT_PANEL, COLOUR_DARK_GREEN), SetMinimalSize(4, 22), SetDataTip(0x0, STR_NULL), EndContainer(),
+		NWidget(WWT_PANEL, COLOUR_DARK_GREEN), SetMinimalSize(4, 22), EndContainer(),
 
 		NWidget(WWT_IMGBTN, COLOUR_DARK_GREEN, WID_RAT_DEMOLISH),
 						SetFill(0, 1), SetMinimalSize(22, 22), SetDataTip(SPR_IMG_DYNAMITE, STR_TOOLTIP_DEMOLISH_BUILDINGS_ETC),

src/station_gui.cpp

@@ -754,12 +754,12 @@ static const NWidgetPart _nested_company_stations_widgets[] = {
 		NWidgetFunction(CargoWidgets),
 		NWidget(WWT_PANEL, COLOUR_GREY, WID_STL_NOCARGOWAITING), SetMinimalSize(14, 0), SetMinimalTextLines(1, 0), SetDataTip(0x0, STR_STATION_LIST_NO_WAITING_CARGO), SetFill(0, 1), EndContainer(),
 		NWidget(WWT_PUSHBTN, COLOUR_GREY, WID_STL_CARGOALL), SetMinimalSize(14, 0), SetMinimalTextLines(1, 0), SetDataTip(0x0, STR_STATION_LIST_SELECT_ALL_TYPES), SetFill(0, 1),
-		NWidget(WWT_PANEL, COLOUR_GREY), SetDataTip(0x0, STR_NULL), SetResize(1, 0), SetFill(1, 1), EndContainer(),
+		NWidget(WWT_PANEL, COLOUR_GREY), SetResize(1, 0), SetFill(1, 1), EndContainer(),
 	EndContainer(),
 	NWidget(NWID_HORIZONTAL),
 		NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_STL_SORTBY), SetMinimalSize(81, 12), SetDataTip(STR_BUTTON_SORT_BY, STR_TOOLTIP_SORT_ORDER),
 		NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_STL_SORTDROPBTN), SetMinimalSize(163, 12), SetDataTip(STR_SORT_BY_NAME, STR_TOOLTIP_SORT_CRITERIA), // widget_data gets overwritten.
-		NWidget(WWT_PANEL, COLOUR_GREY), SetDataTip(0x0, STR_NULL), SetResize(1, 0), SetFill(1, 1), EndContainer(),
+		NWidget(WWT_PANEL, COLOUR_GREY), SetResize(1, 0), SetFill(1, 1), EndContainer(),
 	EndContainer(),
 	NWidget(NWID_HORIZONTAL),
 		NWidget(WWT_PANEL, COLOUR_GREY, WID_STL_LIST), SetMinimalSize(346, 125), SetResize(1, 10), SetDataTip(0x0, STR_STATION_LIST_TOOLTIP), SetScrollbar(WID_STL_SCROLLBAR), EndContainer(),