How to reproduce:
1. Subscribe to radGanttView DoubleClick event.
2. Double click at any point on ragGanttView

Woraround:
1. Create a custom RadGanttView and override the OnMouseDoubleClick method
public class MyRadGanttView : RadGanttView
{

    protected override void OnMouseDoubleClick(MouseEventArgs e)
    {
        if (this.GanttViewElement.ProcessDoubleClick(e))
        {
            return;
        }

        MouseEventHandler item = (MouseEventHandler)base.Events[typeof(Control).GetField("EventMouseDoubleClick", BindingFlags.NonPublic | BindingFlags.Static).GetValue(this)];
        if (item != null)
        {
            item(this, e);
        }
    }
}