rafaelrubirajr

It′s not a good idea make changes in WP′s core files. Instead, use the following code:

function custom_attachment_fields_to_edit($form_fields, $post) {

    $form_fields["image_url"] = '';
    $form_fields["url"] = '';

    $form_fields["url"]["input"] = "hidden";
    $form_fields["url"]["value"] = wp_get_attachment_url($post->ID);

    return $form_fields;
}
add_filter("attachment_fields_to_edit", "custom_attachment_fields_to_edit", null, 2);

Hope it helps ??

Im having that problem too. Are there any solution for this?

In fact, this code is working very well. My apologies.

Case closed ??

Thanks tschramm! I used your code to also implement a next and previous thumbnail with next/prev links ??