xCode 13rc - cannot preview in this file -- missing required components for iOS

It wasn't exactly smooth sailing with XCode 13 beta, but now after downloading XCode 13rc none of my previews work (using swiftUI). I keep getting a message:

Cannot preview in this file - Missing required components for iOS

This is vague to me. What components? What do I need to download?

When you first ran Xcode 13 RC, were you prompted to "Install Additional Components"?
...and did you?

xCode 13rc - cannot preview in this file -- missing required components for iOS
 
 
Q