Bug: Focus restore after elements are reordered does not work in child windows about react

[nkalpakis21]

built an app to get paid for this PR
https://www.n0va-io.com/discover/facebook/react

[Felixdiamond]

Your current implementation only uses the global window object which is probably an issue because focus can be within an iframe or child window, where window would be different.

Try this snippet:

function getActiveElementDeep(win = window) {
  let element = getActiveElement(win.document);
  while (element instanceof win.HTMLIFrameElement) {
    if (isSameOriginFrame(element)) {
      win = element.contentWindow;
      element = getActiveElement(win.document);
    } else {
      return element;
    }
  }
  return element;
}

from react.

[ling1726]

@Felixdiamond to clarify the snippet linked is from the React codebase 😅, that is not my code