Dialog: fix nested popover cannot gain focus

packages/dialog/src/component.vue

@@ -1,6 +1,6 @@
 <template>
   <transition name="dialog-fade">
-    <div class="el-dialog__wrapper" tabindex="-1" v-show="visible" @click.self="handleWrapperClick">
+    <div class="el-dialog__wrapper" v-show="visible" @click.self="handleWrapperClick">
       <div
         class="el-dialog"
         :class="[sizeClass, customClass]"

src/utils/popup/popup-manager.js

@@ -174,16 +174,6 @@ if (!Vue.prototype.$isServer) {
       }
     }
   });
-
-  // keep focusing inside the popup by `tab` key
-  document.addEventListener('focusin', function(event) {
-    const topPopup = getTopPopup();
-
-    if (topPopup && !topPopup.$el.contains(event.target)) {
-      event.stopPropagation();
-      topPopup.$el.focus();
-    }
-  });
 }
 
 export default PopupManager;