On Ubuntu 12.04 LTS, I added an icon theme and activated it using Unity Tweaks. All icons everywhere have changed to my new theme, but the top bar hasn't changed. All icons are still from the original Humanity pack and when a window is maximised, it's "minimise", "maximise" and "close" icons in the top status/menu bar are the plain ones from the Humanity theme.
Here's the screenshot of what a themed window looks like (left corner only):
And here's the screenshot of what the maximised (in top status/menu bar at the top) window looks like:
The rest of the icons on the top bar in the right hand side are also remaining in the original theme and are not changing. How can I force the icons to update in the top bar?