Why does the definition code of layout for IgbDockManager cause the warning "BL0005"?

[jsakamotoIGJP]

When implementing a Blazor app that uses IgbDockManager, the definition code of layout for IgbDockManager caused the warning BL0005: Component parameter 'RootPane' should not be set outside of its component.

> dotnet build
App.razor(12,13): warning BL0005: Component parameter 'RootPane' should not be set outside of its component
...

private readonly IgbDockManagerLayout _InitialLayout = new IgbDockManagerLayout
{
    // 👇 This line causes the warning "BL0005"
    RootPane = new IgbSplitPane
    {
        ...

I believe it must be correct because I did it by referencing the code on the official help document site.

But why do the properties that are involved with DockManager layout information have the [Parameter] attribute regardless it will cause the warning "BL0005"?

Might there be a better way to define the layout of IgbDockManager that avoids such a warning?

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You can reproduce the warning "BL0005" by the Blazor WebAssembly project I attached below.
📦Issue036BlazorWasmApp.zip