Can't get rid of the Windows taskbar, even in fullscreen

[Soothsayer]

Here's an image depicting my frustrating situation.

https://imgur.com/a/kmnK9

So how do I get rid of the taskbar while staying in fullscreen mode? It also stays visible in windowed mode. It doesn't really seem like there an option to overlay my client against my taskbar. This issue only started happening today, clear out of nowhere. [You must be logged in to view images. Log in or Register.]