It is a bit surprising but the good old Themes and Personalization Control Panels have returned in Windows 10 build 10547. Microsoft removed all classic personalization options from the Control Panel in Windows 10, and it was released to end users without these options present. However, with build 10547, the situation has changed.
It is not clear what made Microsoft change their mind, but in Windows 10 build 10547, you can open the classic Control Panel and find everything there related to themes, colors and appearance:
As you might be knowing, Microsoft was about to remove the whole Control Panel in favor of the Settings app. For many Insider builds, Windows 10 came without classic personalization options.
Windows 10 build 10240, which is the RTM build, also comes without those options. Now Microsoft appears to have changed their mind partially.
However, a thing to note is that in Windows 10 build 10547, the Personalization window only looks like the old UI. But it works in a different way. The "classic" buttons do not launch the classic applets. Instead, they launch the appropriate pages of the Settings app. For instance, the "Colors" button just opens the Color page:
The same goes for the Desktop background button. Only "Sounds" and "Screensaver" are still classic dialogs, since they have no replacement in the Settings app:
Many Windows 10 RTM users are not happy with this change of moving Personalization to the Settings app. If you are one of them, take a look at my app "Personalization Panel for Windows 10".
It is a freeware app created by me, which provides a familiar look and feel for Windows 10 RTM users and restores all-in-one access to all personalization features. It opens the classic personalization Control Panels which still work as of Windows 10 RTM. Rather than using the Settings UI, which for example does not allow certain features like setting the Pictures Library as the desktop background slideshow, it is better to use the classic UI which provides full functionality.