Pressing `tab` to select the current dropdown option does not work in the rich text editor

When starting to mention a user with @ or inserting an emoji with : a dropdown is shown to display some suggestions:

Using the "old" markdown editor, pressing tab selects the current suggestion and the the user can continue to write
Using the "new" rich text editor, pressing tab moves to the next UI element, usually a button or a checkbox after the editor, and leaves the dropdown open

Enable the rich text editor
Start mentioning a user with @
Navigate the dropdown with up/down arrows
Try to select the highligthed option pressing tab
The dropdown will remain open and the focus will be moved to the next UI element