private function _getDefautValue($aField)
 {
     $_aSubFields = AdminPageFramework_Utility::getIntegerElements($aField);
     if (count($_aSubFields) == 0) {
         $_aField = $aField;
         return isset($_aField['value']) ? $_aField['value'] : (isset($_aField['default']) ? $_aField['default'] : null);
     }
     $_aDefault = array();
     array_unshift($_aSubFields, $aField);
     foreach ($_aSubFields as $_iIndex => $_aField) {
         $_aDefault[$_iIndex] = isset($_aField['value']) ? $_aField['value'] : (isset($_aField['default']) ? $_aField['default'] : null);
     }
     return $_aDefault;
 }
 /**
  * Returns the default value from the given field definition array.
  * 
  * This is a helper function for the above getDefaultOptions() method.
  * 
  * @since 3.0.0
  */
 private function _getDefautValue($aField)
 {
     // Check if sub-fields exist whose keys are numeric
     $_aSubFields = AdminPageFramework_Utility::getIntegerElements($aField);
     // If there are no sub-fields
     if (count($_aSubFields) == 0) {
         $_aField = $aField;
         return isset($_aField['value']) ? $_aField['value'] : (isset($_aField['default']) ? $_aField['default'] : null);
     }
     // Otherwise, there are sub-fields
     $_aDefault = array();
     array_unshift($_aSubFields, $aField);
     // insert the main field into the very first index.
     foreach ($_aSubFields as $_iIndex => $_aField) {
         $_aDefault[$_iIndex] = isset($_aField['value']) ? $_aField['value'] : (isset($_aField['default']) ? $_aField['default'] : null);
     }
     return $_aDefault;
 }