When navigating the user menu with tab, tab does not provide a way to close the notification menu. This could be be seen as a a keyboard trap per Success Criterion 2.1.2 No Keyboard Trap Level A.

Additional Context regarding why this is important:

• A modal dialog box

A Web application brings up a dialog box. At the bottom of the dialog are two buttons, Cancel and OK. When the dialog has been opened, focus is trapped within the dialog; tabbing from the last control in the dialog takes focus to the first control in the dialog. The dialog is dismissed by activating the Cancel button or the OK button.

To reproduce:

1. Use tab on your keyboard until you open the notification menu.
2. Tab away from the notification menu.
3. Note that the notification menu remains open.

Expected:

1. Use tab on your keyboard until you open the notification menu
2. Tab away from notification menu
3. Notification menu closes

(I have tested on most recently releases of 3.11, 4.0, and 4.1 and confirmed problem exists)