Volume control in notification area

Hi,

We encountered this issue on more than one computers running Windows 8.

Most of the time controlling the volume with the mouse wheel doesn't work when: hovering the notification area AND the taskbar is not in focus. After I click on an empty space of the taskbar, it works again.

I don't know how can it be repeated, but it happens daily for us (my comp, wife's comp, office comp as well).

Thank you!

Adam