A server-action form submit navigates and closes a modal <dialog> that was opened with showModal. Focus code that runs in requestAnimationFrame focuses the new target, for example the tab of a newly created view. Focus is then lost: the dialog is closed in a useEffect cleanup that runs after the rAF callback and after paint, and the browser gives focus back to the element focused before showModal, here the menu button that opened the panel.

In a server-rendered React page, a table row has a link that adds a URL parameter, and that parameter opens a native <dialog> with showModal(). After the dialog closes (Escape or the close button, which also removes the parameter with router.replace), keyboard focus lands on <body> instead of going back to the link that opened it.