XCode editor turns all Swift files into plain text and not able to be edited

My Xcode editor turns into plain white text, and I cannot edit directly on Xcode. All the Swift files are affected, but not other files like Podfile... I did try to resolve my move Xcode to trash and install a new version of Xcode, but I still cannot use it.

Have you tried changing the Theme in: Xcode > Settings > Themes

XCode editor turns all Swift files into plain text and not able to be edited
 
 
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