diff --git a/src/viewport_gui.cpp b/src/viewport_gui.cpp
--- a/src/viewport_gui.cpp
+++ b/src/viewport_gui.cpp
@@ -44,20 +44,20 @@ static const NWidgetPart _nested_extra_v
 		NWidget(WWT_STICKYBOX, COLOUR_GREY, EVW_STICKY),
 	EndContainer(),
 	NWidget(WWT_PANEL, COLOUR_GREY, EVW_BACKGROUND),
-		NWidget(NWID_VIEWPORT, INVALID_COLOUR, EVW_VIEWPORT), SetPadding(2, 2, 2, 2), SetResize(1, 1), SetFill(true, true),
+		NWidget(NWID_VIEWPORT, INVALID_COLOUR, EVW_VIEWPORT), SetPadding(2, 2, 2, 2), SetResize(1, 1), SetFill(1, 1),
 	EndContainer(),
 	NWidget(NWID_HORIZONTAL),
 		NWidget(WWT_PUSHIMGBTN, COLOUR_GREY, EVW_ZOOMIN), SetDataTip(SPR_IMG_ZOOMIN, STR_TOOLBAR_TOOLTIP_ZOOM_THE_VIEW_IN),
 		NWidget(WWT_PUSHIMGBTN, COLOUR_GREY, EVW_ZOOMOUT), SetDataTip(SPR_IMG_ZOOMOUT, STR_TOOLBAR_TOOLTIP_ZOOM_THE_VIEW_OUT),
 		NWidget(NWID_HORIZONTAL, NC_EQUALSIZE),
-			NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, EVW_MAIN_TO_VIEW), SetFill(true, true), SetResize(1, 0),
+			NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, EVW_MAIN_TO_VIEW), SetFill(1, 1), SetResize(1, 0),
 										SetDataTip(STR_EXTRA_VIEW_MOVE_MAIN_TO_VIEW, STR_EXTRA_VIEW_MOVE_MAIN_TO_VIEW_TT),
-			NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, EVW_VIEW_TO_MAIN), SetFill(true, true), SetResize(1, 0),
+			NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, EVW_VIEW_TO_MAIN), SetFill(1, 1), SetResize(1, 0),
 										SetDataTip(STR_EXTRA_VIEW_MOVE_VIEW_TO_MAIN, STR_EXTRA_VIEW_MOVE_VIEW_TO_MAIN_TT),
 		EndContainer(),
 	EndContainer(),
 	NWidget(NWID_HORIZONTAL),
-		NWidget(WWT_PANEL, COLOUR_GREY, EVW_SPACER), SetFill(true, true), SetResize(1, 0), EndContainer(),
+		NWidget(WWT_PANEL, COLOUR_GREY, EVW_SPACER), SetFill(1, 1), SetResize(1, 0), EndContainer(),
 		NWidget(WWT_RESIZEBOX, COLOUR_GREY, EVW_RESIZE),
 	EndContainer(),
 };