(svn r21761) -Add: Wheel-scrolling in the new build station GUI.

src/rail_gui.cpp

@@ -1443,11 +1443,12 @@ static const NWidgetPart _nested_station_builder_widgets[] = {
 				EndContainer(),
 			EndContainer(),
 			NWidget(NWID_SELECTION, INVALID_COLOUR, BRSW_SHOW_NEWST_MATRIX),
-				NWidget(NWID_VERTICAL),
+				/* We need an additional background for the matrix, as the matrix cannot handle the scrollbar due to not being an NWidgetCore. */
+				NWidget(WWT_PANEL, COLOUR_DARK_GREEN), SetScrollbar(BRSW_MATRIX_SCROLL),
 					NWidget(NWID_HORIZONTAL),
 						NWidget(NWID_MATRIX, COLOUR_DARK_GREEN, BRSW_MATRIX), SetScrollbar(BRSW_MATRIX_SCROLL), SetPIP(0, 2, 0), SetPadding(2, 0, 0, 0),
 							NWidget(WWT_PANEL, COLOUR_DARK_GREEN, BRSW_IMAGE), SetMinimalSize(66, 60),
-									SetFill(0, 0), SetResize(0, 0), SetDataTip(0x0, STR_STATION_BUILD_STATION_TYPE_TOOLTIP),
+									SetFill(0, 0), SetResize(0, 0), SetDataTip(0x0, STR_STATION_BUILD_STATION_TYPE_TOOLTIP), SetScrollbar(BRSW_MATRIX_SCROLL),
 							EndContainer(),
 						EndContainer(),
 						NWidget(NWID_VSCROLLBAR, COLOUR_DARK_GREEN, BRSW_MATRIX_SCROLL),