Concerning zen-cart-v1.3.7.1-full-patched-07052007 (and 1.3.6 and 1.3.7)...

Under it's current configuration the 'BUTTON_IMAGE_SEARCH' (button_search.gif) is never drawn.

I believe that '/includes/templates/template_default/sideboxes/tpl_search.php' is missing a small piece of code, specifically a 'zen_image_submit' command in the 'else' section.

Current Code (it is a small file so I have inserted it full for clarity)
Code:
<?php
/**
 * Side Box Template
 *
 * @package templateSystem
 * @copyright Copyright 2003-2006 Zen Cart Development Team
 * @copyright Portions Copyright 2003 osCommerce
 * @license http://www.zen-cart.com/license/2_0.txt GNU Public License V2.0
 * @version $Id: tpl_search.php 4142 2006-08-15 04:32:54Z drbyte $
 */
  $content = "";
  $content .= '<div id="' . str_replace('_', '-', $box_id . 'Content') . '" class="sideBoxContent centeredContent">';
  $content .= zen_draw_form('quick_find', zen_href_link(FILENAME_ADVANCED_SEARCH_RESULT, '', 'NONSSL', false), 'get');
  $content .= zen_draw_hidden_field('main_page',FILENAME_ADVANCED_SEARCH_RESULT);
  $content .= zen_draw_hidden_field('search_in_description', '1') . zen_hide_session_id();

  if (strtolower(IMAGE_USE_CSS_BUTTONS) == 'yes') {
    $content .= zen_draw_input_field('keyword', '', 'size="18" maxlength="100" style="width: ' . ($column_width-30) . 'px"') . '<br />' . zen_image_submit (BUTTON_IMAGE_SEARCH,HEADER_SEARCH_BUTTON);
    $content .= '<br /><a href="' . zen_href_link(FILENAME_ADVANCED_SEARCH) . '">' . BOX_SEARCH_ADVANCED_SEARCH . '</a>';
  } else {
    $content .= zen_draw_input_field('keyword', '', 'size="18" maxlength="100" style="width: ' . ($column_width-30) . 'px" value="' . HEADER_SEARCH_DEFAULT_TEXT . '" onfocus="if (this.value == \'' . HEADER_SEARCH_DEFAULT_TEXT . '\') this.value = \'\';" onblur="if (this.value == \'\') this.value = \'' . HEADER_SEARCH_DEFAULT_TEXT . '\';"') . '<br /><input type="submit" value="' . HEADER_SEARCH_BUTTON . '" style="width: 50px" />';
    $content .= '<br /><a href="' . zen_href_link(FILENAME_ADVANCED_SEARCH) . '">' . BOX_SEARCH_ADVANCED_SEARCH . '</a>';
  }

  $content .= "</form>";
  $content .= '</div>';
?>
Suggested Corrected Code
Code:
<?php
/**
 * Side Box Template
 *
 * @package templateSystem
 * @copyright Copyright 2003-2006 Zen Cart Development Team
 * @copyright Portions Copyright 2003 osCommerce
 * @license http://www.zen-cart.com/license/2_0.txt GNU Public License V2.0
 * @version $Id: tpl_search.php 4142 2006-08-15 04:32:54Z drbyte $
 */
  $content = "";
  $content .= '<div id="' . str_replace('_', '-', $box_id . 'Content') . '" class="sideBoxContent">';
  $content .= zen_draw_form('quick_find', zen_href_link(FILENAME_ADVANCED_SEARCH_RESULT, '', 'NONSSL', false), 'get');
  $content .= zen_draw_hidden_field('main_page',FILENAME_ADVANCED_SEARCH_RESULT);
  $content .= zen_draw_hidden_field('search_in_description', '1') . zen_hide_session_id();

  if (strtolower(IMAGE_USE_CSS_BUTTONS) == 'yes') {
    $content .= zen_draw_input_field('keyword', '', 'size="18" maxlength="100" style="width: ' . ($column_width-30) . 'px"') . zen_image_submit (BUTTON_IMAGE_SEARCH,HEADER_SEARCH_BUTTON);
    $content .= '<br /><a href="' . zen_href_link(FILENAME_ADVANCED_SEARCH) . '" class="smallText">' . BOX_SEARCH_ADVANCED_SEARCH . '</a>';
  } else {
    $content .= zen_draw_input_field('keyword', '', 'size="18" maxlength="100" style="width: ' . ($column_width-30) . 'px" value="' . HEADER_SEARCH_DEFAULT_TEXT . '" onfocus="if (this.value == \'' . HEADER_SEARCH_DEFAULT_TEXT . '\') this.value = \'\';" onblur="if (this.value == \'\') this.value = \'' . HEADER_SEARCH_DEFAULT_TEXT . '\';"') . zen_image_submit(BUTTON_IMAGE_SEARCH, HEADER_SEARCH_BUTTON);
    $content .= '<br /><a href="' . zen_href_link(FILENAME_ADVANCED_SEARCH) . '" class="smallText">' . BOX_SEARCH_ADVANCED_SEARCH . '</a>';
  }

  $content .= "</form>";
  $content .= '</div>';
?>
Additionally, the addition of 'vertical-align:middle;' to the stylesheet fixes alignment issues.

Code:
form, select, input {
font-size: 1em;
padding: 0.1em;
vertical-align:middle;
}