Set transparency
Set the transparency of a selected window. Note that changing the window transparency can make a window unusable (because you cannot see things that are really there), and should be used with caution. If you accidentally set a window to be transparent when you didn't mean to, the transparency will disappear whenever the affected window is closed and reopened.
Arguments
amount — Transparency amount
How transparent should the window be? Ranges from 0 (completely transparent) to 255 (completely opaque).
window — Window
Defaults to the current foreground window. Find windows by searching for the process name, window class and window title. All parts support wildcards or regular expressions. When setting up this command in the user interface, a nice editor is provided for the separate parts. When searching from the command line, the syntax is: \[process name]\[window class]\[window title]. All parts are optional, meaning you can use "\\\Untitled - Notepad" to find the window with that title. Wildcards are supported for each part. You can use regular expressions by surrounding the part with forwards slashes: "\\\/.* - Notepad/" will find any Notepad window, and is equivalent to "\\\* - Notepad".