Fix missing tooltip texts

src/plans_gui.cpp

@@ -49,7 +49,7 @@ static const NWidgetPart _nested_plans_widgets[] = {
 	NWidget(WWT_PANEL, COLOUR_GREY),
 		NWidget(NWID_HORIZONTAL),
 			NWidget(NWID_HORIZONTAL, NC_EQUALSIZE),
-				NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_PLN_NEW), SetResize(1, 0), SetFill(1, 0), SetDataTip(STR_PLANS_NEW_PLAN, STR_NULL),
+				NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_PLN_NEW), SetResize(1, 0), SetFill(1, 0), SetDataTip(STR_PLANS_NEW_PLAN, STR_PLANS_NEW_PLAN_TOOLTIP),
 				NWidget(WWT_TEXTBTN_2, COLOUR_GREY, WID_PLN_ADD_LINES), SetResize(1, 0), SetFill(1, 0), SetDataTip(STR_PLANS_ADD_LINES, STR_PLANS_ADDING_LINES),
 				NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_PLN_VISIBILITY), SetResize(1, 0), SetFill(1, 0), SetDataTip(STR_PLANS_VISIBILITY_PUBLIC, STR_PLANS_VISIBILITY_TOOLTIP),
 				NWidget(WWT_DROPDOWN, COLOUR_GREY, WID_PLN_COLOUR), SetResize(1, 0), SetFill(1, 0), SetDataTip(STR_JUST_STRING, STR_PLANS_COLOUR_TOOLTIP),

src/zoning_gui.cpp

@@ -161,8 +161,8 @@ static const NWidgetPart _nested_zoning_widgets[] = {
 	NWidget(WWT_PANEL, COLOUR_GREY),
 		NWidget(NWID_HORIZONTAL, COLOUR_GREY), SetPIP(10, 3, 10),
 			NWidget(NWID_VERTICAL, COLOUR_GREY), SetPadding(5, 0, 5, 0), SetPIP(0, 5, 0),
-				NWidget(WWT_TEXT, COLOUR_GREY), SetDataTip(STR_ZONING_OUTER, STR_NULL), SetResize(1, 0), SetPadding(1, 6, 1, 6),
-				NWidget(WWT_TEXT, COLOUR_GREY), SetDataTip(STR_ZONING_INNER, STR_NULL), SetResize(1, 0), SetPadding(1, 6, 1, 6),
+				NWidget(WWT_TEXT, COLOUR_GREY), SetDataTip(STR_ZONING_OUTER, STR_ZONING_OUTER_INFO), SetResize(1, 0), SetPadding(1, 6, 1, 6),
+				NWidget(WWT_TEXT, COLOUR_GREY), SetDataTip(STR_ZONING_INNER, STR_ZONING_INNER_INFO), SetResize(1, 0), SetPadding(1, 6, 1, 6),
 			EndContainer(),
 			NWidget(NWID_VERTICAL, COLOUR_GREY), SetPadding(5, 0, 5, 0), SetPIP(0, 5, 0),
 				NWidget(WWT_DROPDOWN, COLOUR_GREY, ZTW_OUTER_DROPDOWN), SetDataTip(STR_JUST_STRING, STR_NULL), SetFill(1, 0),