Summary:
Hover and focus events should not obscure content and should be dismissible.
Details:
Content that appears and disappears in coordination with keyboard focus or pointer hover, such as custom tooltips, sub-menus, overlays and other non-modal popups, often lead to accessibility issues. Therefore, content that appears and disappears on hover or focus must be designed in a way that meets the following conditions:
- Dismissible: A mechanism must be available to dismiss the additional content without moving pointer hover or keyboard focus (such as enabling the Escape key to dismiss the content)
- Hoverable: If pointer hover triggered the additional content, then the pointer must also be able to move over the additional content (i.e. content must not be obscured);
- Persistent: The additional content must remain visible until the hover or focus trigger is removed, the user dismisses the additional content, or its information is no longer valid (such as a status message that changes status).
Exceptions:
This guideline does not apply to custom modal dialogs since they are typically triggered on click events and content that is controlled by the user agent (such as a tooltip displayed via the HTML title attribute) and is not modified by the author.
