View无法在ViewModel中观察所有属性更改

Question

1. 案例：

有一个包含CustomRichTextBox的视图。

public static readonly DependencyProperty NewOutputLogItemProperty = DependencyProperty.Register("NewOutputLogItem",
            typeof(OutputLog ), typeof(CustomRichTextBox), new FrameworkPropertyMetadata(null, OnNewOutputLogAdded));

public OutputLog NewOutputLogItem
{
    get { return (OutputLog )GetValue(NewOutputLogItemProperty ); }

    set { SetValue(NewOutputLogItemProperty , value); }
}

private static void OnNewOutputLogAdded(DependencyObject obj, DependencyPropertyChangedEventArgs args)
{
    var richBox = (CustomRichTextBox)obj;

    var outputLog = (OutputLog )args.NewValue;

    richBox.Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(() =>
    {
        var mainParagraph = richBox.Document.Blocks.FirstBlock as Paragraph;

        if (mainParagraph != null)
        {         

                mainParagraph.Inlines.AddRange(outputLog.GetInlines());
        }
    }));
}

还有ViewModel，它通过MVVM light Messenger接收消息并设置View绑定的属性。

public void ProcessNotificationMessage(OutputLog message)
{        
    NewOutputLog = message;          
}

不幸的是，我发现如果ProcessNotificationMessage工作得太快而且没有描述某些消息，那么View会错过单个消息。

您是否知道如何确保其正常工作？