changes of context

  major changes that, if made without user awareness, can disorient users who are not able to view the entire page simultaneously

  Changes in context include changes of:

  - user agent;
  - viewport;
  - focus;
  - content that changes the meaning of the web page

  A change of content is not always a change of context. Changes in content, such as an expanding outline, dynamic menu, or a tab control do not necessarily change the context, unless they also change one of the above (e.g., focus).

  Opening a new window, moving focus to a different component, going to a new page (including anything that would look to a user as if they had moved to a new page) or significantly re-arranging the content of a page are examples of changes of context.