I selected a bunch of nodes that I wasn't using and that weren't connected and thought that I would see if I could group them.
Well, Blender let me group them alright, but now there is a green background over the rest of my nodes and I cannot select any of them anymore. I deleted the nodes in the group because I couldn't figure out how to "ungroup" them and undo would not undo the grouping operation.
Does anyone have any idea how I can get things back to normal or do I need to start all over again?