Duplication of dropdown `appendToBody` and Vue-Router

Describe the bug The dropdown is not deleted after each switching page with Vue-Router. Therefore multiple dropdown are maintain on the page.

To Reproduce

1. I use append-to-body and :calculate-position="withPopper" as in the guide : Dropdown position
2. When I use the select, a listbox is created
3. I change the page, return back and reuse the same select
4. A new listbox is created

Expected behavior Create and use one dropdown

Screenshots

Desktop (please complete the following information):

• OS: Windows
• Browser Chrome
• Version 86.0.4240.75