Additional content that appears and disappears in coordination with keyboard focus or pointer hover often leads to accessibility issues. Reasons for such issues include:

1. the user may not have intended to trigger the interaction
2. the user may not know new content has appeared
3. the new content may intefere with a user's ability to do a task

Examples of such interactions can include custom tooltips, sub-menus and other nonmodal popups which display on hover and focus. The intent of this success criterion is to ensure that authors who cause additional content to appear and disappear in this manner must design the interaction in such a way that users can:

• perceive the additional content AND
• dismiss it without disrupting their page experience.

There are usually more predictable and accessible means of adding content to the page, which authors are recommended to employ. If an author does choose to make additional content appear and disappear in coordination with hover and keyboard focus, this success criterion specifies three conditions that must be met:

• dismissable
• hoverable
• persistent

Each of these is discussed in a separate section.