diff --git a/src/settings_gui.cpp b/src/settings_gui.cpp
--- a/src/settings_gui.cpp
+++ b/src/settings_gui.cpp
@@ -2222,6 +2222,7 @@ static const NWidgetPart _nested_setting
 	NWidget(NWID_HORIZONTAL),
 		NWidget(WWT_CLOSEBOX, COLOUR_MAUVE),
 		NWidget(WWT_CAPTION, COLOUR_MAUVE), SetDataTip(STR_CONFIG_SETTING_CAPTION, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS),
+		NWidget(WWT_DEFSIZEBOX, COLOUR_MAUVE),
 	EndContainer(),
 	NWidget(WWT_PANEL, COLOUR_MAUVE),
 		NWidget(NWID_HORIZONTAL), SetPadding(WD_TEXTPANEL_TOP, 0, WD_TEXTPANEL_BOTTOM, 0),