How do I open another window in macOS in Swift with Cocoa

Question

I am working on a macOS app that presents a list of customer master records in a table view. Double-clicking a row in the table view should open a new window where the user

Answer 1

Confirmed. This is such a major gotcha in the UI. And it is buggy to boot: Storyboard doesn't contain a controller with identifier 'MainWindow' A whole day wasted troubleshooting this issue.