[Alltribes]

I think I have it. This includes the search by sku mod. This is for 4.0.12, but should work with later versions. I am still testing it, but the categories show up and the wierd stretching bug I had is gone

$ss = split(" ",$data["substring"]);
    $ss_condition = "";
    foreach($ss as $s)
    {
		# Search for substring in some fields...
		$condition = array();
		if (!empty($data["by_title"])) {
			if($current_area == 'C' || $current_area == 'P') {
				$condition[] = "IF($sql_tbl[products_lng].product IS NOT NULL AND $sql_tbl[products_lng].product != '', $sql_tbl[products_lng].product, $sql_tbl[products].product) LIKE '%".$s."%'";
			} else {
				$condition[] = "$sql_tbl[products].product LIKE '%".$s."%'";
			}
		}
		
	 	if (!empty($data["by_shortdescr"])) {
			if($current_area == 'C' || $current_area == 'P') {
				$condition[] = "IF($sql_tbl[products_lng].descr IS NOT NULL AND $sql_tbl[products_lng].descr != '', $sql_tbl[products_lng].descr,  $sql_tbl[products].descr) LIKE '%".$s."%'";
			} else {
				$condition[] = "$sql_tbl[products].descr LIKE '%".$s."%'";
			}
		}

	 	if (!empty($data["by_fulldescr"])) {
			if($current_area == 'C' || $current_area == 'P') {
				$condition[] = "IF($sql_tbl[products_lng].full_descr IS NOT NULL AND $sql_tbl[products_lng].full_descr != '', $sql_tbl[products_lng].full_descr, $sql_tbl[products].fulldescr) LIKE '%".$s."%'";
			} else {
				$condition[] = "$sql_tbl[products].fulldescr LIKE '%".$s."%'";
			}
		}
		
		if (!empty($data["by_productcode"])) {
			if($current_area == 'C' || $current_area == 'P') {
				$condition[] = "IF($sql_tbl[products].productcode IS NOT NULL AND $sql_tbl[products].productcode != '', $sql_tbl[products].productcode, $sql_tbl[products].productcode) LIKE '%".$s."%'";
			} else {
         $condition[] = "$sql_tbl[products].productcode LIKE '%".$s."%'";
			}
		}
		
		if (!empty($data["extra_fields"]) && $active_modules['Extra_Fields']) {
			foreach($data["extra_fields"] as $k => $v)
				$condition[] = "($sql_tbl[extra_field_values].value LIKE '%".$s."%' AND $sql_tbl[extra_fields].fieldid = '$k')";
			$join['extra_field_values'] = "$sql_tbl[products].productid = $sql_tbl[extra_field_values].productid";
			$join['extra_fields'] = "$sql_tbl[extra_field_values].fieldid = $sql_tbl[extra_fields].fieldid AND $sql_tbl[extra_fields].active = 'Y'";
		}
		if (!empty($condition))
			$ss_condition .= " AND (".implode(" OR ", $condition).")";
    }
  $search_condition .= $ss_condition;
		# Search statistics

Mind you this is a mkod to the 4.0.12 code, not the code posted previously.