This addon works absolutely best with HBars or with a minimalistic UI.
What does it do?
-- This slim addon creates "boxes" behind your actionbars for a sleeker look.
-- It creates a border at the top of your screen with a (optional) classcolored border.
Why would i use this addon?
Because you have a minimalistic UI and wish to spice it up, you wish to have some simple borders around HBar (or similar ActionBar addon).
Works with all UIScales and resolutions! =)