Which statement about modal dialog usability is most accurate?

• A. Focus must be trapped within the dialog and Escape should not close it.
• B. Modal dialogs should be used for all tasks regardless of duration.
• C. They should be non-blocking and background content interactive.
• D. Focus must be managed; there should be proper escape-to-close; appropriate size; barrier overlay; and clear titles.

Answer: (D)

Modal dialog usability hinges on controlling how a user interacts with the dialog and the surrounding page. The best practice is to manage keyboard focus so that when the dialog opens, focus is within it and remains there until the dialog is closed, returning to the prior element when dismissed. There should be a straightforward way to close it, typically with Escape, so users aren’t trapped. The dialog should be sized appropriately—neither too small nor unnecessarily large—so content is easily readable without awkward scrolling. A barrier overlay helps signal that the background is inactive and prevents interaction with the page behind the dialog. Clear titles and accessible labeling ensure assistive technologies announce the dialog’s purpose correctly. Together, these elements make the dialog predictable, navigable, and easy to dismiss. Conversely, removing the ability to escape to close, allowing background content to be interactive, using the dialog for any task regardless of duration, or skipping clear labeling and focus management would all impair usability.