diff --git a/src/engine_gui.cpp b/src/engine_gui.cpp
--- a/src/engine_gui.cpp
+++ b/src/engine_gui.cpp
@@ -58,10 +58,10 @@ static const NWidgetPart _nested_engine_
 		NWidget(WWT_CAPTION, COLOUR_LIGHT_BLUE, EPW_CAPTION), SetDataTip(STR_ENGINE_PREVIEW_CAPTION, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS),
 	EndContainer(),
 	NWidget(WWT_PANEL, COLOUR_LIGHT_BLUE, EPW_BACKGROUND),
-		NWidget(WWT_EMPTY, INVALID_COLOUR, EPW_QUESTION), SetMinimalSize(300, 0), SetPadding(8, 8, 8, 8), SetFill(true, false),
+		NWidget(WWT_EMPTY, INVALID_COLOUR, EPW_QUESTION), SetMinimalSize(300, 0), SetPadding(8, 8, 8, 8), SetFill(1, 0),
 		NWidget(NWID_HORIZONTAL, NC_EQUALSIZE), SetPIP(85, 10, 85),
-			NWidget(WWT_PUSHTXTBTN, COLOUR_LIGHT_BLUE, EPW_NO), SetDataTip(STR_QUIT_NO, STR_NULL), SetFill(true, false),
-			NWidget(WWT_PUSHTXTBTN, COLOUR_LIGHT_BLUE, EPW_YES), SetDataTip(STR_QUIT_YES, STR_NULL), SetFill(true, false),
+			NWidget(WWT_PUSHTXTBTN, COLOUR_LIGHT_BLUE, EPW_NO), SetDataTip(STR_QUIT_NO, STR_NULL), SetFill(1, 0),
+			NWidget(WWT_PUSHTXTBTN, COLOUR_LIGHT_BLUE, EPW_YES), SetDataTip(STR_QUIT_YES, STR_NULL), SetFill(1, 0),
 		EndContainer(),
 		NWidget(NWID_SPACER), SetMinimalSize(0, 8),
 	EndContainer(),