I am running Catalina (10.15) with XCode11. After creating a new project and selecting the option to Use SwiftUI, the file opens, but i get an error message in the preview window;'Cannot preview in this file -- active scheme does not build this file. 'the info button says 'Select a scheme that builds a target which contains the current file, or add this file to a target that is built by the current scheme.'i've tried opening numerous new projects, with and without unit tests, but none of them allow it to be previewed. I did see on Twitter that I'm not alone in seeing this issue. Any ideas on steps to troubleshoot it? Thanks all.