The canvas on the right hand side of the screen is now not showing any video. I know it's there, because it outputs fine, but I can't see anything when I'm working. And it's only for this one tab in this project. All the other tabs show video fine.
If you look at the center of the canvas there are buttons at the top. I believe the menu on the right when you click will let you see a list, there is likely a check next to "Alpha". Change it back to "RGB" and you should be set.