If a project file is read-only, it is probably a sample project since all sample project files have the read-only attribute set. This prevents users from accidentally overwriting the project file. In order to be able to save the (customized) project later, the application can copy the read-only file to another, not read-only project file and then continue with the copied version.
If you choose not copy the project file, you can still customize it but in order to save it, you need to save it to another file or remove the read-only attribute from the file first.
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