Hot reload: gray overlay shown with no error messages

[mattgreen]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

dotnet watch with a bare bones Blazor SSR project shows a gray overlay after detecting CSS changes. It appears to be an overlay for an error message, but no message is displayed.

Oddly enough, the change that prompted the hot reload (and subsequent ones) are displayed, which suggests that hot reload is still functional. Following this Reddit post, I tried to hack out the overlay and found I could continue working normally, but I'd like to be able to see hot reload error messages.

Expected Behavior

No overlay shown.

Steps To Reproduce

1. Clone https://github.com/mattgreen/blazor-hot-reload-issue
2. dotnet watch
3. Open the page in a browser
4. In app.css, edit the matt class' font-family property to something like Monaco
5. This may trigger the screen. If not, try changing it again to a different font.

Exceptions (if any)

No response

.NET Version

10.0.100

Anything else?

No response

[phil-scott-78]

I'm seeing this for other scenarios beyond CSS too.

An empty dotnet-compile-error div with no messages in browser console or debug output.

[kijanawoodard]

I think this issue is related: #64051