FocusLayer places a translucent layer between it and all other windows behind the front most window. This can make it easier to tell what you're doing when there are a lot of windows open.
A feature to overlay the current desktop picture instead of a solid color would rock, it would in effect make all background windows appear to be semi transparent.
Using a menu extra was a nice innovation, how about dropping the dock icon entirely and letting us toggle/change prefs via the menu extra?
STEVEN CHAN Excellent software... it allows me to concentrate on one window at a time on my already-cluttered Mac desktop. Great for single-track minds like myself and artists and web developers who wish to concentrate on one piece of work at a time. Has some tiny quibbles, but overall fantastic features and outstanding value for the price. (Version 1.4)