Disable UI to change keyboard navigation indicator setting
User Configuration\Administrative Templates\Windows Components\Windows Explorer
Disables the Hide keyboard navigation indicators until I use the ALT key option in Display in Control Panel.
When this option is selected, the underlining that indicates a keyboard shortcut character (hot key) does not appear on menus until you press ALT.
Effects, such as transitory underlines, are designed to enhance the user's experience but might be confusing or distracting to some users.