Intro
iShadow is a simple addon that does one thing:
Adding a shadowed border to the UI window. Nothing more, nothing less!
Memory usage is nihil, the file is so big because of the high-res texture.
Credits to Ferous for her texture!

Usage
Install and go!
Use the /shadow # command where # is a number 0-100 to set
the level of shadow in percentages.
/shadow 100 sets the maximum shadow, /shadow 0 hides the shadow
and /shadow 50 is half the shadow.
See the pictures in the sidebar. That's all, have fun!