Method OnDragDrop_Vehicle

src/group_gui.cpp:946–1010

	}

	void OnDragDrop_Vehicle(Point pt, WidgetID widget)
	{
		switch (widget) {
			case WID_GL_DEFAULT_VEHICLES: // Ungrouped vehicles
				Command<CMD_ADD_VEHICLE_GROUP>::Post(STR_ERROR_GROUP_CAN_T_ADD_VEHICLE, DEFAULT_GROUP, this->vehicle_sel, _ctrl_pressed || this->grouping == GB_SHARED_ORDERS, VehicleListIdentifier{});

				this->vehicle_sel = VehicleID::Invalid();
				this->group_over = GroupID::Invalid();

				this->SetDirty();
				break;

			case WID_GL_LIST_GROUP: { // Matrix group
				const VehicleID vindex = this->vehicle_sel;
				this->vehicle_sel = VehicleID::Invalid();
				this->group_over = GroupID::Invalid();
				this->SetDirty();

				auto it = this->group_sb->GetScrolledItemFromWidget(this->groups, pt.y, this, WID_GL_LIST_GROUP);
				GroupID new_g = it == this->groups.end() ? NEW_GROUP : it->group->index;

				Command<CMD_ADD_VEHICLE_GROUP>::Post(STR_ERROR_GROUP_CAN_T_ADD_VEHICLE, new_g == NEW_GROUP ? CcAddVehicleNewGroup : nullptr, new_g, vindex, _ctrl_pressed || this->grouping == GB_SHARED_ORDERS, VehicleListIdentifier{});
				break;
			}

			case WID_GL_LIST_VEHICLE: { // Matrix vehicle
				const VehicleID vindex = this->vehicle_sel;
				this->vehicle_sel = VehicleID::Invalid();
				this->group_over = GroupID::Invalid();
				this->SetDirty();

				auto it = this->vscroll->GetScrolledItemFromWidget(this->vehgroups, pt.y, this, WID_GL_LIST_VEHICLE);
				if (it == this->vehgroups.end()) return; // click out of list bound

				const GUIVehicleGroup &vehgroup = *it;
				switch (this->grouping) {
					case GB_NONE: {
						const Vehicle *v = vehgroup.GetSingleVehicle();
						if (!VehicleClicked(v) && vindex == v->index) {
							ShowVehicleViewWindow(v);
						}
						break;
					}

					case GB_SHARED_ORDERS: {
						if (!VehicleClicked(vehgroup)) {
							const Vehicle *v = vehgroup.vehicles_begin[0];
							if (vindex == v->index) {
								if (vehgroup.NumVehicles() == 1) {
									ShowVehicleViewWindow(v);
								} else {
									ShowVehicleListWindow(v);
								}
							}
						}
						break;
					}