messages - Feedback : notification displaying and removal

I have some web applications which allow the users to do some actions. For example, i need to show a paginated items list.

When the user clicks the "Create Item" button, a modal window is displayed. When the user validates the creation form, if all is ok, the modal window is closed. Then, the items list is refreshed and a positive notification appears, floating on top of the screen.

The user is able to close the notification with the "x". I plan to automatically remove the notifcation when the user goes to another page of the application or when he reloads a part of the the current page.

Should I plan to automatically remove the notification when : - the user goes to the next page of the paginated list ? - the user scrolls down on the current page (for example if we show 100 items / page) ? - the user opens a new modal window ?

What are the best pratices on this topic ?