Visual style

A visual style is a set of bitmaps and other graphics used to modify the Windows user interface, which was introduced in Windows XP. They are more advanced compared to a scheme applied on top of the classic theme, which was the original built-in customization mechanism used prior to Windows XP. The behavior and effects of visual styles later changed significantly in the Windows Longhorn and Windows Vista operating systems due to the inclusion of a desktop compositor.

The visual style engine is implemented in, while the resources for the individual styles are contained in resource-only DLL files with the   extension. A single visual style can contain multiple variants.