After moving keyboard focus through focusable elements in a modal, the focus moves away from the modal to the browser's toolbar.

Expected :
Focus should stay within a modal until the modal is closed.

This is part of the suggested techniques to meet wcag 1.3.1 (see "Note on focus management").

The modal demo in Bootstrap 4.6 is also reflecting the expected behaviour.

How to reproduce
See HTML Modals in the UI component library

Or:

• Go to a text editor field (e.g. course settings > description)
• Click on the Image button to open the modal
• Press tab until the focus reaches the browser tabs

Browsers:
We were able to reproduce this issue with Chrome, Firefox, and Safari on MacOs and Chrome on Windows