I've found that this issue was already fixed in 0.4.0 [Reference 1](https://github.com/aspnet/Blazor/issues/784) [Reference 2](https://github.com/aspnet/Blazor/issues/753) But it still present. Blazor 3.0.0-preview4 Visual Studio 2019 16.1.0 preview2 Latest vsix extension installed Files where issue happened: [Button.razor](https://github.com/vova-lantsov-dev/bookkeeping-blazor/blob/feature-blazor-3.0.0-preview4/BookkeepingNasheDetstvo.Client/Components/ForButtons/Button.razor) [HalfButton.razor](https://github.com/vova-lantsov-dev/bookkeeping-blazor/blob/feature-blazor-3.0.0-preview4/BookkeepingNasheDetstvo.Client/Components/ForButtons/HalfButton.razor) [Project repository](https://github.com/vova-lantsov-dev/bookkeeping-blazor/tree/feature-blazor-3.0.0-preview4) I also tried to solve this problem by deleting .vs / bin / obj directories and restarting VS.