Blazor: bind-Xxx is not mapped to XxxChanged

I have two razor pages: one embedded into the other. I want to bind an inner property to an outer property.

All I get, when I start the app, is an exception

Object of type 'BlazorApp2.Components.Controls.DismissibleAlert' does not have a property matching the name 'bind-Message'

My outer page:

@page "/"@using BlazorApp2.Components.Controls<PageTitle>Home</PageTitle><h1>Hello, world!</h1><br/>@Message<br/><DismissibleAlert bind-Message="@Message"></DismissibleAlert><button @onclick="DoWhatIMean" class="btn btn-info" >Change Text</button>@code{    private void DoWhatIMean()        => Message = "You clicked the button!";    [Parameter]    public string Message { get; set; } = "Default Message";}

The DismissibleAlert looks like this:

<h3>DismissibleAlert</h3>@Message<button type="button" class="btn-close" @onclick="Dismiss"></button><br/>@code {    [Parameter] public string Message { get; set; } = string.Empty;    [Parameter] public EventCallback<string> MessageChanged { get; set; }    public async Task Dismiss()    {        Message = string.Empty;        await MessageChanged.InvokeAsync();    }}

I'm running out of ideas why this does not run... I really appreciate your tips