Divide wp_dropdown_categories to include alphabetical optgroups

fixedCategoryDropdown.php

// put this in your functions.php file
function fixedCategoryDropdown() {
  $categories = get_categories('depth=1');
  $catcount = count($categories);
  $categorymenu = wp_dropdown_categories(
    array(
      // See http://codex.wordpress.org/Function_Reference/wp_dropdown_categories
      //   for all the available options
      // These are the ones that makes sence for this example
      'orderby' => 'name',
      'echo' => false,
    )
  );
  // save some kb's by removing the level class name given by WP,
  //   if you only have one leveled categories -  optional
  //$categorymenu = preg_replace("#\sclass\=\"level\-0\"#","",$categorymenu);
  // and some more bytes by removing   
  //$categorymenu = html_entity_decode($categorymenu, ENT_COMPAT, 'UTF-8');
  // Now, lets make some optgroup's!
  $exploded_html = '<option';
  $new_html_arr = array();
  $options = explode($exploded_html, $categorymenu);
  $new_html = array_shift($options).$exploded_html.array_shift($options);
  for ($i=0; $i < sizeof($options); $i++) {
    preg_match("#(\'|\")\>(\w)#i", $options[$i], $first_letter_match);
    $first_letter = strtolower($first_letter_match[2]);
    if ($i == 0) {
      $new_html_arr[] = $first_letter;
      $new_html_arr[] = $options[$i];
      $current_letter = $first_letter;
    } elseif ($current_letter == $first_letter) {
      $new_html_arr[] = $options[$i];
    } else {
      $new_html_arr[] = $first_letter;
      $new_html_arr[] = $options[$i];
      $current_letter = $first_letter;
    }
  }
  for ($i = 0; $i < sizeof($new_html_arr); $i++) {
    if (strlen($new_html_arr[$i]) == 1) {
      $new_html .= $i ? "</optgroup>" : "";
      $new_html .= '<optgroup label="'.strtoupper($new_html_arr[$i]).'">';
    } else {
      $new_html .= $exploded_html.$new_html_arr[$i];
    }
  }
  // Return the new html, call this function in your theme = ' echo fixedCategoryDropdown(); '
  return $new_html;
}