Winaero ColorSync is very tiny application (441 kb) which is native and portable.
It serves only one purpose: to read the background color of your Start screen in Windows 8.1 and set it as the window color for desktop apps.
It has only few options:
Run at startup – will run the application every time Windows starts.
Hide tray icon – will hide the tray icon of application. The application will remember this setting and will not show the tray icon even you restart it. To make it shown again, run Winaero ColorSync twice.
Winaero ColorSync supports Windows 8.1 x86 and x64. No separate version for x64 is required, the application works well on both versions.