Control Spy is a tool that helps developers understand common controls: how to apply styles to them, and how they respond to messages and notifications. Using Control Spy, you can immediately see how different styles affect the behavior and appearance of each control, and also how you can change the state of each control by sending messages.

Two versions of Control Spy are available, one for Comctl32.dll version 5.x and one for Comctl32.dll version 6.0 and later. ControlSpyV6.exe has a built-in application manifest so that it uses the newer, themed controls. ControlSpyV5.exe does not have this manifst and so defaults to the older version.