EF Core Power Tools EntityFrameworkCore.Design.OperationException suddenly occurring on "Add DbContext Diagram"

Question

I've been using EF Core Power Tools to assist with learning EF Core. The data project is simply a class library that contains the base DbContext used by the associated web app, plus the migrations folder.

It's been working fine until suddenly this error occurs when I "Add DbContext Diagram"

System.InvalidOperationException: Error:
Microsoft.EntityFrameworkCore.Design.OperationException: Unable to create an object of type 'EventFinderContext'. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?linkid=851728
 ---> System.InvalidOperationException: Unable to resolve service for type 'Microsoft.EntityFrameworkCore.DbContextOptions`1[EventFinderData.EventFinderContext]' while attempting to activate 'EventFinderData.EventFinderContext'.
   at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.ConstructorMatcher.CreateInstance(IServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.CreateInstance(IServiceProvider provider, Type instanceType, Object[] parameters)
   at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetServiceOrCreateInstance(IServiceProvider provider, Type type)
   at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.<>c__DisplayClass21_4.<FindContextTypes>b__13()
   --- End of inner exception stack trace ---
   at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.<>c__DisplayClass21_4.<FindContextTypes>b__13()
   at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.CreateContext(Func`1 factory)
   at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.CreateContext(String contextType)
   at Modelling.EfCoreModelBuilder.BuildResult(String outputPath, String startupOutputPath, Boolean generateDdl) in C:\Code\EFCorePowerTools\src\GUI\efpt30.core\EFCoreModelBuilder.cs:line 41
   at Modelling.Program.Main(String[] args) in C:\Code\EFCorePowerTools\src\GUI\efpt30.core\Program.cs:line 56

   at async Task EFCorePowerTools.Handlers.ModelAnalyzerHandler.GenerateAsync(string outputPath, Project project, GenerationType generationType)

I'm not sure even where to start looking to investigate, so any pointers would be appreciated please. The solution builds okay, the database seems fine, and the associated Blazor project also runs fine.

Not sure if its helpful but in my data project, the constructor for the DbContext is this:

namespace EventFinderData
{
    public class EventFinderContext : DbContext
    {
        public EventFinderContext(DbContextOptions<EventFinderContext> options) : base(options)
        {
        }
    }
}

Answer 1

As advised by ErikEJ (the author of Power Tools) the diagram function only works on the executable project. Once I had added a web application project to my solution, the original console and data layer projects in that solution no longer worked for creating the diagram.