Change: Use NC_BIGFIRST in group window.

This means we no longer need to manually calculate the size of other
widgets in the window to determine how much space we need, as the widget
system will automatically fill as much as possible.

src/group_gui.cpp

@@ -48,7 +48,7 @@ static const NWidgetPart _nested_group_widgets[] = {
 	EndContainer(),
 	NWidget(NWID_HORIZONTAL),
 		/* left part */
-		NWidget(NWID_VERTICAL),
+		NWidget(NWID_VERTICAL, NC_BIGFIRST),
 			NWidget(WWT_PANEL, COLOUR_GREY, WID_GL_ALL_VEHICLES), SetFill(1, 0), EndContainer(),
 			NWidget(WWT_PANEL, COLOUR_GREY, WID_GL_DEFAULT_VEHICLES), SetFill(1, 0), EndContainer(),
 			NWidget(NWID_HORIZONTAL),
@@ -383,26 +383,11 @@ public:
 	void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize) override
 	{
 		switch (widget) {
-			case WID_GL_LIST_GROUP: {
+			case WID_GL_LIST_GROUP:
 				size->width = this->ComputeGroupInfoSize();
 				resize->height = this->tiny_step_height;
-
-				/* Minimum height is the height of the list widget minus all and default vehicles... */
-				size->height = 4 * GetVehicleListHeight(this->vli.vtype, this->tiny_step_height);
-
-				/* ... minus the buttons at the bottom ... */
-				uint max_icon_height = GetSpriteSize(this->GetWidget<NWidgetCore>(WID_GL_CREATE_GROUP)->widget_data).height;
-				max_icon_height = std::max(max_icon_height, GetSpriteSize(this->GetWidget<NWidgetCore>(WID_GL_RENAME_GROUP)->widget_data).height);
-				max_icon_height = std::max(max_icon_height, GetSpriteSize(this->GetWidget<NWidgetCore>(WID_GL_DELETE_GROUP)->widget_data).height);
-				max_icon_height = std::max(max_icon_height, GetSpriteSize(this->GetWidget<NWidgetCore>(WID_GL_REPLACE_PROTECTION)->widget_data).height);
-
-				/* ... minus the height of the group info ... */
-				max_icon_height += (FONT_HEIGHT_NORMAL * 3) + WD_FRAMERECT_TOP + WD_FRAMERECT_BOTTOM;
-
-				/* Get a multiple of tiny_step_height of that amount */
-				size->height = Ceil(size->height - max_icon_height, tiny_step_height);
+				fill->height = this->tiny_step_height;
 				break;
-			}
 
 			case WID_GL_ALL_VEHICLES:
 			case WID_GL_DEFAULT_VEHICLES: