API Manager, gui interface to Win32 APIs, to examine or change window properties
The easiest is to download the provided binaries from my home page.
To compile it you need Lazarus.
APIM provides access to most of the GUI related functions of the Win32 API, for the windows of all processes.
You can e.g. select a window, and enable the stay-on-top and transparency flags for it.
Or you can kill a process.
Or you can select the start button and make it invisible.
Or on older Windows version, you can select an edit box containing a password, and disable the password flag, letting you see the password in plaintext. (it uses dll injection, to also show the password in not trivial cases)