Codechange: Use PIP spacing instead of spacers in tree picker window. (#12623)

src/tree_gui.cpp

@@ -293,19 +293,16 @@ static constexpr NWidgetPart _nested_build_trees_widgets[] = {
 		NWidget(WWT_STICKYBOX, COLOUR_DARK_GREEN),
 	EndContainer(),
 	NWidget(WWT_PANEL, COLOUR_DARK_GREEN),
-		NWidget(NWID_VERTICAL), SetPadding(2),
+		NWidget(NWID_VERTICAL), SetPIP(0, 1, 0), SetPadding(2),
 			NWidgetFunction(MakeTreeTypeButtons),
-			NWidget(NWID_SPACER), SetMinimalSize(0, 1),
 			NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_BT_TYPE_RANDOM), SetDataTip(STR_TREES_RANDOM_TYPE, STR_TREES_RANDOM_TYPE_TOOLTIP),
 			NWidget(NWID_SELECTION, INVALID_COLOUR, WID_BT_SE_PANE),
-				NWidget(NWID_VERTICAL),
-					NWidget(NWID_SPACER), SetMinimalSize(0, 1),
+				NWidget(NWID_VERTICAL), SetPIP(0, 1, 0),
 					NWidget(NWID_HORIZONTAL, NC_EQUALSIZE),
 						NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_BT_MODE_NORMAL), SetFill(1, 0), SetDataTip(STR_TREES_MODE_NORMAL_BUTTON, STR_TREES_MODE_NORMAL_TOOLTIP),
 						NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_BT_MODE_FOREST_SM), SetFill(1, 0), SetDataTip(STR_TREES_MODE_FOREST_SM_BUTTON, STR_TREES_MODE_FOREST_SM_TOOLTIP),
 						NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_BT_MODE_FOREST_LG), SetFill(1, 0), SetDataTip(STR_TREES_MODE_FOREST_LG_BUTTON, STR_TREES_MODE_FOREST_LG_TOOLTIP),
 					EndContainer(),
-					NWidget(NWID_SPACER), SetMinimalSize(0, 1),
 					NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_BT_MANY_RANDOM), SetDataTip(STR_TREES_RANDOM_TREES_BUTTON, STR_TREES_RANDOM_TREES_TOOLTIP),
 				EndContainer(),
 			EndContainer(),