anchor.diff:      this.show();
     }
   
  +  /** Before actually displaying the notification, this method checks whether there are duplicates
  +    * of the notification in the specified container. It also launches autohide() if applicable.
  +    */
     void show() {
   
       // Don't do anything if a similar message has been displayed before.
  
positive.code:     autohide();
    }
  
    void hide() {
      if(this.permanent == null || this.permanent == false) {
        behave("hide");
  
negative.code: part of nest_ui;
  
  /** The purpose of this component is to display user notifications, such as when a user successfully logs in or incorrectly fills the form.
    * Such notifications usually appear on top of the page and disappear after some time. This component if flexible enough to
    * allow you to tweak for how long a notification should be displayed, whether it should stay there until user leaves the page (permanent),
    * and also tweak the message type (so that you can add CSS code to have different notification colors for different types of messages). 
    *
    * The best part of this component is that you can invoke the notification in two different ways: programmatically, by writing
    * Dart code and initializing the component or by having a DOM element in your DOM. The latter is convenient to automatically
    * display messages on page load and is, probably, the most common way in which this component is going to be used.
    */
  class SimpleNotificationComponent extends Component with AutoShowHide {
  
    final List attribute_names = ["message", "autohide_delay", "permanent", "container_selector", "message_type", "ignore_duplicates"];
          List native_events   = ["close.click"];
          Map default_attribute_values = {
            "container_name": "#simple_notifications_container",
            "permanent": false,   // will not allow this notification to be closed
            "autohide_delay": 10, // will hide the notification
            "message_type": "neutral", // adds css class "message-type-neutral"
            "ignore_duplicates": true  // if set to false, allows duplicate notifications to be displayed in the same container
          };
  
    Future autohide_future;
  