Setting group selection as 'Required' does not work

Subscribing

If you want to make the set group required, you can create a simple module and use hook_form_alter to force any form field to be required.

function mymodulename_form_alter(&$form, &$form_state, $form_id) {
$form['og_nodeapi']['visible']['og_abt'][0]['og_group_type_group_node_']['#required'] = TRUE;
}