@K1979, you can correct that issue by editing your /YOUR_ADMIN/news_box_manager.php, locating this code section (starting at line 537):
Code:
// -----
// Editing an existing article or inserting a new one ... noting that we can also come back here
// from an article's insert/update "Preview" to make changes prior to saving in the database.
//
if ($action == 'modify' || $action == 'updateedit' || $action == 'new' || $action == 'newedit') {
    if ($action == 'modify' || $action == 'updateedit') {
        $form_action = 'updatepreview' . "&nID=$nID";
        $hidden_field = zen_draw_hidden_field('nID', $nID);
        $cancel_link = zen_href_link($news_box_script_name, $page_get_params . "nID=$nID");
    } else {
and adding the highlighted line:
Code:
// -----
// Editing an existing article or inserting a new one ... noting that we can also come back here
// from an article's insert/update "Preview" to make changes prior to saving in the database.
//
if ($action == 'modify' || $action == 'updateedit' || $action == 'new' || $action == 'newedit') {
    if ($action == 'modify' || $action == 'updateedit') {
        $form_action = 'updatepreview' . "&nID=$nID";
        $hidden_field = zen_draw_hidden_field('nID', $nID);
        $hidden_field .= ($all_news_types) ? '' : zen_draw_hidden_field('news_content_type', $news_box_type);
        $cancel_link = zen_href_link($news_box_script_name, $page_get_params . "nID=$nID");
    } else {
I'll be getting v3.0.3 of News Box Manager released, containing this change as well as the documentation updates identified by @gernot.