Razor editor does not know about changes until VS has been restarted

[MarvinKlein1508]

Probably this topic is related to @davidwengier

I noticed some behaviour within the new razor editor within VS Insiders 11104.47

When you have a component like this:

/* More stuff here. STripped down for demo purposes */
@ChildContent
	
@if (FooterContent is not null)
{
	@FooterContent
}
		

@code {

	[Parameter]
	public RenderFragment ChildContent { get; set; } = default!;

	[Parameter]
	public RenderFragment FooterContent { get; set; } = default!;

}

Notice I have a RenderFragment here called ChildContent. Later on I've added the second RenderFragment called FooterContent. However the new RenderFragment won't get highlighted in VS and does not show up in Intellisense until I restart Visual Studio. Even compiling the project doesn't help. I have to manually restart VS. I get this behaviour consitantly whenever I add new RenderFragment sections to any of my components.

[davidwengier]

@MarvinKlein1508 Can you explain (or screenshot) exactly what you mean when you say the new fragment won't get "highlighted"?

I don't think I can repro the issue you are seeing (eg, when I add a property it shows up in intellisense immediately), but at the same time nothing special about the use of those fragments is highlighted. What exactly are you expecting here?

Also, I just did this in a single file, like in your example above. Just to make sure, do you still see the issue if you use a single file? Or are you doing things across files/projects and just simplified for the issue?

[MarvinKlein1508]

@davidwengier Sure! Here is a small video. I guess it has something todo with the component being part of a razor class library. This is happning consistently for me. Everytime I change some stuff in it I need to restart VS to get them highlighted in VS. The code would compile without any issues but it's pretty hard to get the work done this way.

2025-10-10.08-03-11.mp4

[MarvinKlein1508]

This also goes in the other way. I just reset all my changes in the git window and now the component will be shown in Intellisense until I restart VS.

[davidwengier]

Thanks for the extra info! Across projects, and particularly with a RazorClassLibrary, definitely adds a few more variables than what I was trying :)

Can you double check one last thing for me. Go to Tools -> Options, and search for "cohost", and see if the preview feature is on. If it's not on, can you turn it on, restart VS, and try again?

[MarvinKlein1508]

@davidwengier yes it is turned on.

[chsienki]

Thanks @MarvinKlein1508 for the info.

This definitely points to being a generator cache issue. Investigating.

[davidwengier]

@MarvinKlein1508 Do you get squiggles or errors in the error list if you manually type out the render fragments?

I wonder if this is the same #12316

[MarvinKlein1508]

I see them like this:

The refactor menu doesn't show up any namespaces (which makes sence since it has been already imported in _Imports.razor: