Pierre RASO

@shua somthing is missing in your code (and mine for radio buttons) : when editing again, selected velue does not appear as selected. Default value appears as selected instead
So, I had to change in functions_post.php, line 433
if ($use_defaults == false && $saved_value == $one_option_internal_name) {
to
if ($use_defaults == false && $saved_value == $dropdown_value_esc) {

and change line 414 :
if ($saved_value == $one_radio_option_key) { $selected = " checked='checked' "; }
to
if ($saved_value == esc_html($one_radio_option_val["value"])) { $selected = " checked='checked' "; }

Great tip but :

• you could do the same for radio buttons
  change in functions_post.php, line 418:
  echo "<input $selected name='$field_name' id='$radio_field_unique_id' type='radio' value='$one_radio_option_key' />";
  to :
  echo "<input $selected name='$field_name' id='$radio_field_unique_id' type='radio' value='".esc_html($one_radio_option_val["value"])."' />";
• I think you will have problems with simple fields front-end functions (simple_fields_get_post_value and simple_fields_get_post_group_values) which use special processing to retrieve stored values for dropdown and radio buttons.
  for this change in functions_post.php, lines 792 and 862 (simple fields 0.3.9) or lines 779 and 849 (simple fields 0.3.8) :
  $saved_values[$saved_i] = $one_field[$get_value_key][$saved_values[$saved_i]]["value"];
  to
  if ($one_field[$get_value_key][$saved_values[$saved_i]]["value"]) {$saved_values[$saved_i] = $one_field[$get_value_key][$saved_values[$saved_i]]["value"];}

This works fine for me with 0.3.8