[int_19h]

There's a reason why Win7 dialed transparency down from Vista.

[Kwpolska]

[citation needed]

Vista had a black taskbar with some transparency, 7 made it glass.

If you maximised a window on Vista, the maximised window's border became dark (black/with an accent colour tint) and opaque, the taskbar and sidebar went opaque as well. 7 got rid of that.