private void RadRichTextBox_ProtectionStateChanged(object sender, EventArgs e)
{
    if (this.radRichTextBox.CurrentUser == null)
    {
        this.radRichTextBox.CurrentUser = new Telerik.Windows.Documents.Model.UserInfo(string.Empty, string.Empty, string.Empty, string.Empty);
    }
}

...
this.radRichTextBox.CommandExecuting += RadRichTextBox_CommandExecuting;
...

...
private void RadRichTextBox_CommandExecuting(object sender, CommandExecutingEventArgs e)
{
    if (e.Command is SaveCommand)
    {
        this.radRichTextBox.ChangeBibliographicStyle(new APAFifthEditionStyle());
    }
}