title: Oracle APEX - display user message from PL/SQL dynamic action
body: <p>I have a dynamic action that executes PL/SQL procedure and my DA has a check to see if specific page items are not null. If it is null, the procedure will not be executed and I want to display a message to the user. Ideally I's just add a server-side condition to my DA but the issue is that I need to, somehow, notify the user. I tried using APEX_ERROR and display error message inline in notification but that did not work - message does not get displayed.</p>
  <pre><code>IF :P1_ITEM1 IS NOT NULL AND :P1_ITEM2 IS NOT NULL AND :P1_ITEM3 IS NOT  NULL 
  THEN
      MY_PROCEDURE();
  ELSE
      APEX_ERROR.ADD ERROR( p_message =&gt; 'Some required fields are NULL',
                            p_display_location =&gt; apex_error.c_inline_in_notification);
  END IF;
  </code></pre>
  <p>How can I display a notification to the user if the condition is not met?</p>