People keep forgetting the AccentColoeInactive zips on my themes. They are there so the inactive window title bar has the same or approximately the color as the active window. In this case though I used silver, because the different background create different accent colors(task bar, active window, start menu et all.
tweaking to do once, but the colors of the installed themes are used.
As Cliff said, Office 2016 uses newer user interface.