How to avoid flickering when using an asynchronous binding
<p>I've created an example to illustrate my problem.</p>

<p>ViewModel:</p>

<pre><code>public class VM : INotifyPropertyChanged
{
    private double _value = 1;
    public double Value
    {
        get { return _value; }
        set
        {
            _value = value; 
            OnPropertyChanged();
        }
    }

    public VM()
    {
        var timer = new DispatcherTimer();
        timer.Interval = TimeSpan.FromTicks(1);
        timer.Tick += (s, e) =&gt; { Value += 1; };
        timer.Start();
    }

    // OnPropertyChanged stuff ... 
    }
}
</code></pre>

<p>View:</p>

<pre><code>&lt;Window.DataContext&gt;
    &lt;namespace:VM/&gt;
&lt;/Window.DataContext&gt;
&lt;Grid&gt;
    &lt;TextBox Text="{Binding Value, IsAsync=True, FallbackValue=Test}"/&gt;
&lt;/Grid&gt;
</code></pre>

<p>When running my application the text in the textbox flickers. During the update process the FallbackValue is displayed, which makes no sense to me.</p>

<p>Does anyone knows the purposes or what are the benefits that during the update process the FallbackValue is displayed? Is there a way to display the old Value during an async update process?</p>