Non modal dialogs allowed
non-modal-dialogs-allowed
Non-modal dialogs are allowed — they do not interrupt interaction behind them. MUI cites NN/g modal vs non-modal and demos a persistent cookie banner. Dual-cite extra-harvest NN/g 7 numbered modal rules; this row is MUI's explicit non-modal permission + cookie-banner pattern.
Description
Non-modal dialogs are allowed: they do not interrupt interaction behind them. A persistent cookie banner is the named pattern for staying visible without blocking the page. Implementing that pattern as a blocking modal breaks the permission. Fail if a cookie-banner or non-modal pattern is implemented as a blocking modal, or if “non-modal allowed” is treated as permission to modal nonessential off-flow content. Use non-modal when the page behind must stay usable.
When to use
Using a persistent non-blocking pattern such as a cookie banner.
Not when
Not as permission to modal nonessential off-flow content that should stay in-page.
Agent hint
Allow non-modal patterns that leave the page usable; do not force a blocking modal.
A non-modal (e.g. persistent cookie banner) does not block interaction behind it when that pattern is used.
A cookie-banner/non-modal pattern implemented as a blocking modal; or treating "non-modal allowed" as permission to modal nonessential off-flow (NN/g 5–7 still apply).
Citations
MUI — Dialog
https://mui.com/material-ui/react-dialog/