title: How to remove the default “Plugin activated” message in WordPress?
body: <p>I have successfully found out how to show a custom message when my plugin is activated, but I don't the default message to appear. Is there a way to do is?</p>
  
  <pre><code>function plugin_activate() {
    add_option('plugin_activated', true);
  } register_activation_hook(__FILE__, 'plugin_activate');
  
  function plugin_activated() {
    if(get_option('plugin_activated', false)) {
      delete_option('plugin_activated');
      add_action('admin_notices', create_function('', 'echo 
      \'&lt;div class="updated fade"&gt;&lt;p&gt;My plugin is &lt;strong&gt;activated&lt;/strong&gt;. &lt;a href="options-general.php?my-plugin"&gt;Configure it →&lt;/a&gt;&lt;/div&gt;\';'));
    }
  } add_action('admin_init', 'plugin_activated');
  </code></pre>