[TrapFocus] Don't contain if document isn't focused

Author: eps1lon

packages/material-ui/src/Modal/Modal.test.js

@@ -548,7 +548,12 @@ describe('<Modal />', () => {
         clock.restore();
       });
 
-      it('contains the focus if the active element is removed', () => {
+      it('contains the focus if the active element is removed', function test() {
+        if (/jsdom/.test(window.navigator.userAgent)) {
+          // see https://github.com/jsdom/jsdom/issues/2953
+          this.skip();
+        }
+
         function WithRemovableElement({ hideButton = false }) {
           return (
             <Modal open>

packages/material-ui/src/Modal/TrapFocus.js

@@ -67,7 +67,12 @@ function TrapFocus(props) {
     }
 
     const contain = () => {
-      if (disableEnforceFocus || !isEnabled() || ignoreNextEnforceFocus.current) {
+      if (
+        !doc.hasFocus() ||
+        disableEnforceFocus ||
+        !isEnabled() ||
+        ignoreNextEnforceFocus.current
+      ) {
         ignoreNextEnforceFocus.current = false;
         return;
       }