Fill Dropdown programatically -> not shows all entries by scrolling bottom | Unity 5.4.0f3

Hello,

i fill a dropdown with dynaic content from json and it does not show all entries? How can i fix that?
Attached the screenshots where you can see that tehere are more entries and here is the code:

Code (CSharp):

1.  
2. /// <summary>
3.     /// Setups the country dropdown.
4.     /// </summary>
5.     private void SetupCityDropdown( JsonData data ) {
6.  
7.         DropdownCities.gameObject.SetActive (true);
8.  
9.         DropdownCities.options.Clear();
10.  
11.         List <City> tmp_city_data = new List<City> ();
12.         city_data = new List<City> ();
13.  
14.         City start_select = new City();
15.         start_select.Postalcode = "nothing_selected";
16.         start_select.PlaceName = "Bitte wählen...";
17.  
18.         for (int i = 0; i < data["all_cities"].Count; i++)
19.         {
20.             Debug.Log("placeName= "+ data["all_cities"][i]["placeName"]);
21.  
22.             City newCity = new City ();
23.             newCity.ID = i;
24.  
25.             newCity.CountryCode = data ["all_cities"] [i] ["countryCode"].ToString();
26.             newCity.PlaceName = data ["all_cities"] [i] ["placeName"].ToString();
27.             newCity.Postalcode = data ["all_cities"] [i] ["postalcode"].ToString();
28.  
29.             newCity.Lng = float.Parse(data ["all_cities"] [i] ["lng"].ToString());
30.             newCity.Lat = float.Parse(data ["all_cities"] [i] ["lat"].ToString());
31.  
32.             tmp_city_data.Add (newCity);
33.         }
34.  
35.         //sort list by ??
36.         city_data = tmp_city_data.OrderBy(o=>o.PlaceName).ToList();
37.  
38.         city_data.Insert(0, start_select);
39.  
40.         //write to DropdownCountry
41.         int counter = 0;
42.         foreach(City city in city_data)
43.         {
44.             if (counter > 0) {
45.                 DropdownCities.options.Add(new Dropdown.OptionData(city.Postalcode + ", " +city.PlaceName));
46.             }
47.             counter++;
48.         }
49.  
50.         LabelDropDownCities.text = city_data [1].PlaceName;
51.         DropdownCities.GetComponent<Dropdown> ().value = 1;
52.  
53.         pageViewController.hideLoading ();
54.  
55.         DropdownCities.Show ();
56.     }

 

try use default scroll bar, see if the problem still persist?