If you have a RadRotator with several RadImageButtonElement and you try to go to the next imagebuttons quickly (by calling Next() several times), you end with an empty RadRotator.
Workaround: 
  DateTime dt = DateTime.Now;
        int interval = 500;
        private void radButton1_Click(object sender, EventArgs e)
        {
            TimeSpan span = DateTime.Now - dt;
            if (span.TotalMilliseconds > interval)
            {
                this.radRotator1.Next();
                dt = DateTime.Now;
            }
        }
        private void radButton2_Click(object sender, EventArgs e)
        {
            TimeSpan span = DateTime.Now - dt;
            if (span.TotalMilliseconds > interval)
            {
                this.radRotator1.Previous();
                dt = DateTime.Now;
            }
        }