Wrong category in list

Hello,

Just purchashed the gravity form (very awesome btw) But I nog added a list to my form filled with post. like explained on http://www.gravityhelp.com/forums/topic/automatically-populate-a-dropdown-with-post-titles

It seems to word fine however the post which are shown are from the wrong category! When you to to http://www.geneeskundebaan.nl/demo/solliciteer/ the first field is supposed to load the post from category "vacatures" but is showing post from the category "portfolio" instead.

I use this code in mij functions.php:

'//Adds a filter to form id 14. Replace 14 with your actual form id
add_filter("gform_pre_render_1", populate_dropdown);
function populate_dropdown($form){

//Reading posts for "Business" category;
$posts = get_posts("category=vacatures");

//Creating drop down item array.
$items = array();

//Adding initial blank value.
$items[] = array("text" => "", "value" => "");

//Adding post titles to the items array
foreach($posts as $post)
$items[] = array("value" => $post->post_title, "text" => $post->post_title);

//Adding items to field id 8. Replace 8 with your actual field id. You can get the field id by looking at the input name in the markup.
foreach($form["fields"] as &$field)
if($field["id"] == 35){
$field["type"] = "select";
$field["choices"] = $items;
}

return $form;
}'

Thanks!, I used the documentation in the wordpress codex. This was the sulution:

add_filter("gform_pre_render_1", populate_dropdown);
function populate_dropdown($form){

$args = array(
    'numberposts'     => 5,
    'offset'          => 0,
    'category'        => 1,
    'orderby'         => 'post_date',
    'order'           => 'DESC',
    'post_type'       => 'post',
    'post_status'     => 'publish' );

    //Reading posts for "Business" category;
$posts = get_posts( $args );

    //Creating drop down item array.
    $items = array();

    //Adding initial blank value.
    $items[] = array("text" => "", "value" => "");

    //Adding post titles to the items array
    foreach($posts as $post)
        $items[] = array("value" => $post->post_title, "text" => $post->post_title);

    //Adding items to field id 8. Replace 8 with your actual field id. You can get the field id by looking at the input name in the markup.
    foreach($form["fields"] as &$field)
        if($field["id"] == 35){
            $field["type"] = "select";
            $field["choices"] = $items;
        }

    return $form;
}

?>

As you can see now its easy to order, and to set the max amount of items..