Target window gone
 

My target window has seemingly vanished. I've moved windows around to see if it was behind something, I've changed UIs, I've changed window resolution/size...I can't find it anywhere. What's the fix I'm not seeing?

Have you tried the toggle for it? Alt-T

That did it. I didn't even know there was a toggle or how I did it. Thanks, mate.

Most of the UI elements can be hidden with a combination of keystrokes. These are all listed in Options > Keys.

In there, you can change the keystroke to something you won't hit by mistake, or even eliminated it by clicking on that command and hitting Escape. I've turned them all off so I can't accidentally make any of my windows disappear.