How to disable the Submit button on a the delete page form?
Yes, you are understanding the behavior of the '#disabled' key correctly. I tried the code you describe and it "just worked."

function custom_form_node_delete_confirm_alter(&amp;$form, $form_state) {

  dsm($form['actions']['submit']);
  $form['actions']['submit']['#disabled'] = TRUE;
  dsm($form['actions']['submit']);
}




My guess as to why the alteration is not creating the desired end result is that your function signature is not using the "&amp;" with the $form variable. That character is needed for the $form variable to be "passed by reference" which allows for the changes to the variable to stick outside the function.