There is a substantial, unannounced context change on focus

Rule

Focusing on an element MUST NOT automatically trigger a change of context, unless the user has been adequately advised ahead of time.

Background

When a major change of context occurs - such as a opening a new window, moving focus to another element, a submitting a form - while a keyboard user is tabbing through a page, they may become quite disoriented or, much worse, they may be completely blocked from using the content. Any component that is able to trigger an event when it receives focus must not change the user's context. This will ensure that keyboard users can successfully navigate their way through a page in a predictable manner.

How to Fix

Fix this issue by ensuring that when a page element receives focus, it does not result in a change in context including:

1. submitting a form automatically;
2. launching a new window;
3. changing focus to another component when a component receives focus; or
4. any other change that could confuse or disorient the user.