Hi all,

The reason for the "Completed" status is that it is confirmed that the behavior you are seeing is a result of a change in how .NET 10 handles component parameters, rather than a bug.

In earlier .NET versions, Blazor was more permissive and allowed component parameters—such as OnClick - to be overridden internally without issue. In .NET 10, the framework enforces stricter rules around parameter overriding, which affects components that internally replace event handlers.

Our Window component uses built-in actions (Close, Minimize, Maximize), and these actions require the component to substitute the OnClick handler with an internal method so the action can execute correctly. This has always been the intended mechanism and is part of how the component is designed.

What changed is simply that .NET 10 now exposes this behavior more clearly.

Because of that:

• The built-in action’s OnClick handler is now correctly reserved for the internal action (closing, minimizing, maximizing).

• Custom logic for these actions should continue to use the dedicated events already designed for this: VisibleChanged and StateChanged.

• There is no loss of functionality - all scenarios remain achievable using the recommended events.

We will update the component documentation to make this clearer.

Regards,
Hristian Stefanov
Progress Telerik