@if (Parent.ActivePage == this)
{
    @TabContent
}

@code {
    [CascadingParameter]        private         TabbedMenu     Parent       { get; set; } = null!;
    [Parameter, EditorRequired] public required RenderFragment TabContent { get; set; }
    [Parameter, EditorRequired] public RenderFragment? Title { get; set; }

    protected override void OnInitialized()
    {
        Parent.AddPage(this);
    }
}