Radzen Blazor for Visual Studio - Design time build failed

Hi,
Finally a paid user thanks to Black Friday.
So I've installed the Visual Studio extension - I had to update VS to latest by the way, it complained about missing a .NET 9 component.

This solution works fine by the way but no longer with this extension installed.

My issue now is opening a razor component, it's shows a blank white box in the top half of the screen and after a long time, it gives me a design time build failed.

Checking the logs for this, there's all sorts of errors for projects which are unloaded from my solution. It should not be touching or looking at those..

But I'm also getting these issues:
It's giving me a error CS8795 for all my Riok Mapperly mappings. This is using a source generator and works fine if running the app normally.

Weirdly, on one project, I get Program.cs(41,60): error CS0103: The name 'args' does not exist in the current context but there is no line 41..

On another project, Program.cs(145,13): error CS0136: A local or parameter named 'services' cannot be declared in this scope because that name is used in an enclosing local scope to define a local or parameter
Program.cs(145,24): error CS0841: Cannot use local variable 'services' before it is declared
but this defined on line 101..
var services = builder.Services;

A console app in the solution is getting this error:
error CS5001: Program does not contain a static 'Main' method suitable for an entry point
It has a main - it's an async task though..

Not sure why it needs to get involved with so much?

Anyway, had to disable for now to keep working.

SO I disabled and restarted VS.. The component I tried to open above now had this error:

An error occurred in '<removed>' while attempting to open '<removed>.razor'
System.Runtime.InteropServices.COMException (0x80041FEA): Exception from HRESULT: 0x80041FEA
   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
   at Microsoft.VisualStudio.PlatformUI.Packages.ShellService.EditorFactories.EditorFactory.<CreateEditorInstanceAsync>d__43.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.Platform.WindowManagement.WindowFrame.<>c__DisplayClass86_0.<<CreateEditorInstanceAsync>g__CreateEditorInstanceAsync|1>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.Platform.WindowManagement.WindowFrame.<CreateEditorInstanceAsync>d__86.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.Platform.WindowManagement.WindowFrame.<LoadDocumentFrameInternalAsync>d__85.MoveNext()

Error Code: 0x80041FEA

Thankfully closing and re-opening it cleared this..

That's expected. .NET 9 is required.

Because it needs to build your project to display it in design time. More info is available here: Troubleshooting | Radzen Blazor for Visual Studio

In any case you can send us your project so we can check why it fails to build in design time.

ok, no time now to revisit..

We have released a few updates of the extension since then. Could you try the latest version? We would really want to troubleshoot further as this exception shouldn't happen when opening a .razor file.