I don’t think you defined the dropdowns correctly.
The following is a working example:
(these are taken from the file custom/include/language/en_us.lang.php)
$GLOBALS['app_list_strings']['press_agency_continents_list']=array (
'' => '',
'Asia' => 'Asia',
'Europe' => 'Europe',
'Africa' => 'Africa',
'Oceania' => 'Oceania',
'NorthAmerica' => 'North America',
'Antarctica' => 'Antarctica',
'SouthAmerica' => 'South America',
'U' => 'Unknown Continent',
);
$GLOBALS['app_list_strings']['press_agency_countries_list']=array (
'' => '',
'U_U' => 'Unknown Country and Continent',
'Europe_U' => 'Unknown Europe',
'Africa_U' => 'Unknown Africa',
'Oceania_U' => 'Unknown Oceania',
'NorthAmerica_U' => 'Unknown North America',
'Antarctica_U' => 'Unknown Antarctica',
'SouthAmerica_U' => 'Unknown South America',
'Europe_ALA' => 'Åland Islands',
'Asia_AFG' => 'Afghanistan',
'Europe_ALB' => 'Albania',
'Africa_DZA' => 'Algeria',
'Oceania_ASM' => 'American Samoa',
'Europe_AND' => 'Andorra',
'Africa_AGO' => 'Angola',
'NorthAmerica_AIA' => 'Anguilla',
'Antarctica_ATA' => 'Antarctica',
'NorthAmerica_ATG' => 'Antigua and Barbuda',
'SouthAmerica_ARG' => 'Argentina',
'Asia_ARM' => 'Armenia',
'NorthAmerica_ABW' => 'Aruba',
'Oceania_AUS' => 'Australia',
'Europe_AUT' => 'Austria',
'Asia_AZE' => 'Azerbaijan',
'NorthAmerica_BHS' => 'Bahamas',
'Asia_BHR' => 'Bahrain',
'Asia_BGD' => 'Bangladesh',
'NorthAmerica_BRB' => 'Barbados',
'Europe_BLR' => 'Belarus',
'Europe_BEL' => 'Belgium',
'NorthAmerica_BLZ' => 'Belize',
'Africa_BEN' => 'Benin',
'NorthAmerica_BMU' => 'Bermuda',
'Asia_BTN' => 'Bhutan',
'SouthAmerica_BOL' => 'Bolivia',
'Europe_BIH' => 'Bosnia and Herzegovina',
'Africa_BWA' => 'Botswana',
'Antarctica_BVT' => 'Bouvet Island',
'SouthAmerica_BRA' => 'Brazil',
'Asia_IOT' => 'British Indian Ocean Territory',
'Asia_BRN' => 'Brunei Darussalam',
'Europe_BGR' => 'Bulgaria',
'Africa_BFA' => 'Burkina Faso',
'Africa_BDI' => 'Burundi',
'Asia_KHM' => 'Cambodia',
'Africa_CMR' => 'Cameroon',
'NorthAmerica_CAN' => 'Canada',
'Africa_CPV' => 'Cape Verde',
'NorthAmerica_CYM' => 'Cayman Islands',
'Africa_CAF' => 'Central African Republic',
'Africa_TCD' => 'Chad',
'SouthAmerica_CHL' => 'Chile',
'Asia_CHN' => 'China',
'Asia_CXR' => 'Christmas Island',
'Asia_CCK' => 'Cocos (Keeling) Islands',
'SouthAmerica_COL' => 'Colombia',
'Africa_COM' => 'Comoros',
'Africa_COG' => 'Congo',
'Africa_COD' => 'The Democratic Republic of The Congo',
'Oceania_COK' => 'Cook Islands',
'NorthAmerica_CRI' => 'Costa Rica',
'Africa_CIV' => 'Cote D\'ivoire',
'Europe_HRV' => 'Croatia',
'NorthAmerica_CUB' => 'Cuba',
'Asia_CYP' => 'Cyprus',
'Europe_CZE' => 'Czech Republic',
'Europe_DNK' => 'Denmark',
'Africa_DJI' => 'Djibouti',
'NorthAmerica_DMA' => 'Dominica',
'NorthAmerica_DOM' => 'Dominican Republic',
'SouthAmerica_ECU' => 'Ecuador',
'Africa_EGY' => 'Egypt',
'NorthAmerica_SLV' => 'El Salvador',
'Africa_GNQ' => 'Equatorial Guinea',
'Africa_ERI' => 'Eritrea',
'Europe_EST' => 'Estonia',
'Africa_ETH' => 'Ethiopia',
'SouthAmerica_FLK' => 'Falkland Islands (Malvinas)',
'Europe_FRO' => 'Faroe Islands',
'Oceania_FJI' => 'Fiji',
'Europe_FIN' => 'Finland',
'Europe_FRA' => 'France',
'SouthAmerica_GUF' => 'French Guiana',
'Oceania_PYF' => 'French Polynesia',
'Antarctica_ATF' => 'French Southern Territories',
'Africa_GAB' => 'Gabon',
'Africa_GMB' => 'Gambia',
'Asia_GEO' => 'Georgia',
'Europe_DEU' => 'Germany',
'Africa_GHA' => 'Ghana',
'Europe_GIB' => 'Gibraltar',
'Europe_GRC' => 'Greece',
'NorthAmerica_GRL' => 'Greenland',
'NorthAmerica_GRD' => 'Grenada',
'NorthAmerica_GLP' => 'Guadeloupe',
'Oceania_GUM' => 'Guam',
'NorthAmerica_GTM' => 'Guatemala',
'Europe_GGY' => 'Guernsey',
'Africa_GIN' => 'Guinea',
'Africa_GNB' => 'Guinea-bissau',
'SouthAmerica_GUY' => 'Guyana',
'NorthAmerica_HTI' => 'Haiti',
'Antarctica_HMD' => 'Heard Island and Mcdonald Islands',
'Europe_VAT' => 'Holy See (Vatican City State)',
'NorthAmerica_HND' => 'Honduras',
'Asia_HKG' => 'Hong Kong',
'Europe_HUN' => 'Hungary',
'Europe_ISL' => 'Iceland',
'Asia_IND' => 'India',
'Asia_IDN' => 'Indonesia',
'Asia_IRN' => 'Iran',
'Asia_IRQ' => 'Iraq',
'Europe_IRL' => 'Ireland',
'Europe_IMN' => 'Isle of Man',
'Asia_ISR' => 'Israel',
'Europe_ITA' => 'Italy',
'NorthAmerica_JAM' => 'Jamaica',
'Asia_JPN' => 'Japan',
'Europe_JEY' => 'Jersey',
'Asia_JOR' => 'Jordan',
'Asia_KAZ' => 'Kazakhstan',
'Africa_KEN' => 'Kenya',
'Oceania_KIR' => 'Kiribati',
'Asia_PRK' => 'Democratic People\'s Republic of Korea',
'Asia_KOR' => 'Republic of Korea',
'Asia_KWT' => 'Kuwait',
'Asia_KGZ' => 'Kyrgyzstan',
'Asia_LAO' => 'Lao People\'s Democratic Republic',
'Europe_LVA' => 'Latvia',
'Asia_LBN' => 'Lebanon',
'Africa_LSO' => 'Lesotho',
'Africa_LBR' => 'Liberia',
'Africa_LBY' => 'Libya',
'Europe_LIE' => 'Liechtenstein',
'Europe_LTU' => 'Lithuania',
'Europe_LUX' => 'Luxembourg',
'Asia_MAC' => 'Macao',
'Europe_MKD' => 'Macedonia',
'Africa_MDG' => 'Madagascar',
'Africa_MWI' => 'Malawi',
'Asia_MYS' => 'Malaysia',
'Asia_MDV' => 'Maldives',
'Africa_MLI' => 'Mali',
'Europe_MLT' => 'Malta',
'Oceania_MHL' => 'Marshall Islands',
'NorthAmerica_MTQ' => 'Martinique',
'Africa_MRT' => 'Mauritania',
'Africa_MUS' => 'Mauritius',
'Africa_MYT' => 'Mayotte',
'NorthAmerica_MEX' => 'Mexico',
'Oceania_FSM' => 'Micronesia',
'Europe_MDA' => 'Moldova',
'Europe_MCO' => 'Monaco',
'Asia_MNG' => 'Mongolia',
'Europe_MNE' => 'Montenegro',
'NorthAmerica_MSR' => 'Montserrat',
'Africa_MAR' => 'Morocco',
'Africa_MOZ' => 'Mozambique',
'Asia_MMR' => 'Myanmar',
'Africa_NAM' => 'Namibia',
'Oceania_NRU' => 'Nauru',
'Asia_NPL' => 'Nepal',
'Europe_NLD' => 'Netherlands',
'NorthAmerica_ANT' => 'Netherlands Antilles',
'Oceania_NCL' => 'New Caledonia',
'Oceania_NZL' => 'New Zealand',
'NorthAmerica_NIC' => 'Nicaragua',
'Africa_NER' => 'Niger',
'Africa_NGA' => 'Nigeria',
'Oceania_NIU' => 'Niue',
'Oceania_NFK' => 'Norfolk Island',
'Oceania_MNP' => 'Northern Mariana Islands',
'Europe_NOR' => 'Norway',
'Asia_OMN' => 'Oman',
'Asia_PAK' => 'Pakistan',
'Oceania_PLW' => 'Palau',
'Asia_PSE' => 'Palestinia',
'NorthAmerica_PAN' => 'Panama',
'Oceania_PNG' => 'Papua New Guinea',
'SouthAmerica_PRY' => 'Paraguay',
'SouthAmerica_PER' => 'Peru',
'Asia_PHL' => 'Philippines',
'Oceania_PCN' => 'Pitcairn',
'Europe_POL' => 'Poland',
'Europe_PRT' => 'Portugal',
'NorthAmerica_PRI' => 'Puerto Rico',
'Asia_QAT' => 'Qatar',
'Africa_REU' => 'Reunion',
'Europe_ROM' => 'Romania',
'Europe_RUS' => 'Russian Federation',
'Africa_RWA' => 'Rwanda',
'Africa_SHN' => 'Saint Helena',
'NorthAmerica_KNA' => 'Saint Kitts and Nevis',
'NorthAmerica_LCA' => 'Saint Lucia',
'NorthAmerica_SPM' => 'Saint Pierre and Miquelon',
'NorthAmerica_VCT' => 'Saint Vincent and The Grenadines',
'Oceania_WSM' => 'Samoa',
'Europe_SMR' => 'San Marino',
'Africa_STP' => 'Sao Tome and Principe',
'Asia_SAU' => 'Saudi Arabia',
'Africa_SEN' => 'Senegal',
'Europe_SRB' => 'Serbia',
'Africa_SYC' => 'Seychelles',
'Africa_SLE' => 'Sierra Leone',
'Asia_SGP' => 'Singapore',
'Europe_SVK' => 'Slovakia',
'Europe_SVN' => 'Slovenia',
'Oceania_SLB' => 'Solomon Islands',
'Africa_SOM' => 'Somalia',
'Africa_ZAF' => 'South Africa',
'Africa_SSD' => 'South Sudan',
'Antarctica_SGS' => 'South Georgia and The South Sandwich Islands',
'Europe_ESP' => 'Spain',
'Asia_LKA' => 'Sri Lanka',
'Africa_SDN' => 'Sudan',
'SouthAmerica_SUR' => 'Suriname',
'Europe_SJM' => 'Svalbard and Jan Mayen',
'Africa_SWZ' => 'Swaziland',
'Europe_SWE' => 'Sweden',
'Europe_CHE' => 'Switzerland',
'Asia_SYR' => 'Syrian Arab Republic',
'Asia_TWN' => 'Taiwan, Province of China',
'Asia_TJK' => 'Tajikistan',
'Africa_TZA' => 'Tanzania, United Republic of',
'Asia_THA' => 'Thailand',
'Asia_TLS' => 'Timor-leste',
'Africa_TGO' => 'Togo',
'Oceania_TKL' => 'Tokelau',
'Oceania_TON' => 'Tonga',
'NorthAmerica_TTO' => 'Trinidad and Tobago',
'Africa_TUN' => 'Tunisia',
'Asia_TUR' => 'Turkey',
'Asia_TKM' => 'Turkmenistan',
'NorthAmerica_TCA' => 'Turks and Caicos Islands',
'Oceania_TUV' => 'Tuvalu',
'Africa_UGA' => 'Uganda',
'Europe_UKR' => 'Ukraine',
'Asia_ARE' => 'United Arab Emirates',
'Europe_GBR' => 'United Kingdom',
'NorthAmerica_USA' => 'United States',
'Oceania_UMI' => 'United States Minor Outlying Islands',
'SouthAmerica_URY' => 'Uruguay',
'Asia_UZB' => 'Uzbekistan',
'Oceania_VUT' => 'Vanuatu',
'SouthAmerica_VEN' => 'Venezuela',
'Asia_VNM' => 'Viet Nam',
'NorthAmerica_VGB' => 'Virgin Islands, British',
'NorthAmerica_VIR' => 'Virgin Islands, U.S.',
'Oceania_WLF' => 'Wallis and Futuna',
'Africa_ESH' => 'Western Sahara',
'Asia_YEM' => 'Yemen',
'Africa_ZMB' => 'Zambia',
'Africa_ZWE' => 'Zimbabwe',
'Asia_U' => 'Unknown Asia',
'Europe_U' => 'Unknown Europe',
'Africa_U' => 'Unknown Africa',
'Oceania_U' => 'Unknown Oceania',
'NorthAmerica_U' => 'Unknown North America',
'Antarctica_U' => 'Unknown Antarctica',
'SouthAmerica_U' => 'Unknown South America',
);
Additionally you have to go in Studio and define the parent field as a normal dropdown:
see image
Once you have defined the parent field you define the child field as a DynamicDropdown and in the Parent Dropdown form field you enter the name of the parent field followed by_c (note that this is the name of the parent dropdown field in the way you have defined it in Studio and not the name of the dropdown, which can be found in custom/include/language/en_us.lang.php
see image:
Once done I recommend that you edit the database table called fields_meta_data and set to NULL the values of the two fields (Parent DropDown and child DynamicDropDown)
see image:
If you have other grand children or grand grand children you proceed in the same way.