Solution:
In nextgen-public-uploader/inc/npu-upload.php
Comment or delete lines 199, 272:
$strOutput .= "\n<input type=\"hidden\" name=\"galleryselect\" value=\"{$gal_id}\">";
and between the lines 200, 201 (for Shortcode Form) and 269, 270 (for Widget Form):
Exemple:
$strOutput .= "\n\t<div class=\"uploader\">";
<--- paste
$strOutput .= "\n\t<input type=\"file\" name=\"imagefiles\" id=\"imagefiles\"/>";
Paste this:
$strOutput .= "\n\tChoose gallery:: <select name=\"galleryselect\">";
$sql = "SELECT gid, title FROM wp_ngg_gallery ORDER BY title";
$result = mysql_query($sql);
while ($array = mysql_fetch_array($result)) {
$strOutput .= "\n\t<option value=\"".$array['gid']."\">".$array['title']."</option>";
}
$strOutput .= "\n\t</select><br><br>";
Thats all!