Somehow along the learning curve I inadvertently renamed Main.Storyboard to Main.storyboardc. After having renamed the file, I cannot view the storyboard source code.
When I rename Main.Storyboardc back to Main.Storyboard, it shows up in red text and behaves as though the file has been deleted. I searched Google and Stack Overflow, but it may be such a one-off issue that I've not found any help. Of course, I could just add a new storyboard and redo the effort, but if someone has a suggestion, I will try that first. Thank you.