I had the Output box set to show underneath my code. I accidentally pulled it out from there and it became its own window. I can close the window and go to View, click Output, and it comes back, still as a window! How can I set it back?
All windows within Visual Studio are dockable. You need to find the sweet spot for where the overlay menu shows up allowing you to dock your window in a certain position.
Drag the window towards the bottom until this overlay menu shows up, then choose the bottom position and it will dock below again.