I'm working with the Office 2013 theme, perhaps the problem is not visible in other theme.
I have a WPF application with a combo box that can be enabled/disabled with a click on a button on the ribbon. Clicking on the button doesn't change the focus (that's important).
I the combo box is enabled and has the focus, pressing the ribbon button disables the combo box, but it stilll shows that it has the focus. When moving the focus to another control, the combo box still shows the focus state.
I think that the focus state should only be displayed when the combo box is enabled.