Method OnPaint

src/group_gui.cpp:581–635

	}

	void OnPaint() override
	{
		/* If we select the all vehicles, this->list will contain all vehicles of the owner
		 * else this->list will contain all vehicles which belong to the selected group */
		this->BuildVehicleList();
		this->SortVehicleList();

		this->BuildGroupList(this->owner);

		this->group_sb->SetCount(this->groups.size());
		this->vscroll->SetCount(this->vehgroups.size());

		/* The drop down menu is out, *but* it may not be used, retract it. */
		if (this->vehicles.empty() && this->IsWidgetLowered(WID_GL_MANAGE_VEHICLES_DROPDOWN)) {
			this->RaiseWidget(WID_GL_MANAGE_VEHICLES_DROPDOWN);
			this->CloseChildWindows(WC_DROPDOWN_MENU);
		}

		/* Disable all lists management button when the list is empty */
		this->SetWidgetsDisabledState(this->vehicles.empty() || _local_company != this->vli.company,
				WID_GL_STOP_ALL,
				WID_GL_START_ALL,
				WID_GL_MANAGE_VEHICLES_DROPDOWN);

		/* Disable the group specific function when we select the default group or all vehicles */
		GroupID group = this->vli.ToGroupID();
		this->SetWidgetsDisabledState(IsDefaultGroupID(group) || IsAllGroupID(group) || _local_company != this->vli.company,
				WID_GL_DELETE_GROUP,
				WID_GL_RENAME_GROUP,
				WID_GL_LIVERY_GROUP,
				WID_GL_REPLACE_PROTECTION);

		/* Disable remaining buttons for non-local companies
		 * Needed while changing _local_company, eg. by cheats
		 * All procedures (eg. move vehicle to another group)
		 *  verify, whether you are the owner of the vehicle,
		 *  so it doesn't have to be disabled
		 */
		this->SetWidgetsDisabledState(_local_company != this->vli.company,
				WID_GL_CREATE_GROUP,
				WID_GL_AVAILABLE_VEHICLES);

		/* If not a default group and the group has replace protection, show an enabled replace sprite. */
		uint16_t protect_sprite = SPR_GROUP_REPLACE_OFF_TRAIN;
		if (!IsDefaultGroupID(group) && !IsAllGroupID(group) && Group::Get(group)->flags.Test(GroupFlag::ReplaceProtection)) protect_sprite = SPR_GROUP_REPLACE_ON_TRAIN;
		this->GetWidget<NWidgetCore>(WID_GL_REPLACE_PROTECTION)->SetSprite(protect_sprite + this->vli.vtype);

		/* Set text of "group by" dropdown widget. */
		this->GetWidget<NWidgetCore>(WID_GL_GROUP_BY_DROPDOWN)->SetString(std::data(this->vehicle_group_by_names)[this->grouping]);

		/* Set text of "sort by" dropdown widget. */
		this->GetWidget<NWidgetCore>(WID_GL_SORT_BY_DROPDOWN)->SetString(this->GetVehicleSorterNames()[this->vehgroups.SortType()]);

		this->DrawWidgets();
	}

	void DrawWidget(const Rect &r, WidgetID widget) const override
	{