public <T extends Field> T createEntityField(Class<?> type, Class<?> fieldType){
if(fieldType == null) fieldType = DEFAULT_ENTITY_FIELD_TYPE;
if(fieldType.isAssignableFrom(ComboBox.class)){
EntityField field = new EntityField(type);
field.setImmediate(true);
return (T) field;
} else {
return null;
}