Usage of b-dropdown or b-nav-item-dropdown throws TypeError: Invalid calling object in IE11

Describe the bug

I am setting up a menu navigation bar that contains a dropdown, and it requires support of IE11. When rendering in IE11, it is throwing a [Vue warn]: Error in v-on handler: "TypeError: Invalid calling object" when clicking on the top-level dropdown item in the menu. This does not occur in Chrome.

I have all the polyfills installed (core-js, regenerator-runtime) and imported in my index.js. I am using Webpack.

Steps to reproduce the bug

1. Use BootstrapVue in a new Vue component
2. Ensure core-js and regenerator-runtime/runtime are imported
3. For a simple reproduction, grab the example dropdown nav markup from the docs (https://bootstrap-vue.org/docs/components/nav#comp-ref-b-nav-item-dropdown)

// in main entry point
import 'core-js'
import 'regenerator-runtime/runtime'

import Vue from 'vue'
import BootstrapVue from 'bootstrap-vue'

new Vue({
  el: '#app'
}

// in menu component
<template>
  <div>
  <b-nav pills>
    <b-nav-item active>Active</b-nav-item>
    <b-nav-item>Link</b-nav-item>
    <b-nav-item-dropdown
      id="my-nav-dropdown"
      text="Dropdown"
      toggle-class="nav-link-custom"
      right
    >
      <b-dropdown-item>One</b-dropdown-item>
      <b-dropdown-item>Two</b-dropdown-item>
      <b-dropdown-divider></b-dropdown-divider>
      <b-dropdown-item>Three</b-dropdown-item>
    </b-nav-item-dropdown>
  </b-nav>
</div>
</template>

Expected behavior

The dropdown is fully interactive and navigable in IE11 without any console errors.

Versions

Libraries:

• BootstrapVue: 2.1.0
• Bootstrap: 4.4.1
• Vue: 2.6.10
• Webpack: 4.40.2

Environment:

• Device: Windows
• OS: Windows 10
• Browser: IE 11
• Version: 11.476.18362.0 (Update version 11.0.160)

[AlexLu202]

I assume you are using babel 7. For some reason, babel 7 stops transpiling imported module. That’s probably the reason why

[jgsestrich]

FWIW, this error is also being thrown when a b-modal pops up a few minutes later after a session timeout.

I have run into this exact problem; did you every resolve the issue?