WinExplorer

WinExplorer is a utility that shows all system's windows in hierarchical display. For every window in the hierarchy, you can view its properties, like handle, class name, caption, size, position and more. You can also modify some properties, like Caption and Visible/Enabled. This utility is released as freeware with full source code. You can freely use, distribute, and modify the source code of this utility without restrictions. However, if you release to the public a modified version of this utility, you should specify the original copyright notice.