<select> Default Value
This question already has an answer here:
 You don't use an argument $x of your Types function which as i guess is a selected value.  Try to replace your function with this code:  
function Types($x) {    
    global $mysqli;
    $type = " SELECT type FROM types ";
    if ($type_results = $mysqli->query($type)) {
        while ($row = $type_results->fetch_assoc()) {
            $selected = ($row["type"] == $x) ? 'selected="selected"' : '';
            printf ("<option %s>%s</option>", $selected, $row["type"]);
        }
        $type_results->free();
    }    
}
 and of course provide selected value to function Types in your html code.  
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