Scaffolding in Blazor is unaware of (implicit inheritance?)

[eberleitguy]

I'm not amazing at searching, but i didn't find anything similar to my eyes. Apologies in advance if i overlooked.

This bug is pretty simple.
When using the Quick Action "Extract block to code-behind", the resulting code-behind doesn't have explicitly defined inheritance, and appears, in the file, to be a bare class. Of course, blazor is all fancy and happily runs, for the most part, despite this. (not clear why, i did get into a couple of states where roslyn was underlining these "incorrect" methods, but a restart of VS returned functionality).

Find a screen-to-gif of the issue in action below.

For the most part i was following Dan Roth's Blazor front end youtube series (Starting here: https://www.youtube.com/watch?v=sIIfnGqEIds) , but early on took the path of extracting the "Counter" c# code to a codebehind file. I ran into the issue much later when i was following along with the scaffolding in video 9.

Find entire sample project attached.

There are branches tagging the specific problems.
TrainingSample.zip

#Environment:
Microsoft Visual Studio Community 2022
Version 17.9.7
VisualStudio.17.Release/17.9.7+34902.65
Microsoft .NET Framework
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OS Info:
WIndows 11 Home 22H2 Build 22521.2283