bool OtherControlsAllowed (ControlBuilder cb)
{
if (cb == null)
return true;
if (!typeof (System.Web.UI.WebControls.Content).IsAssignableFrom (cb.ControlType))
return true;
if (BuilderHasOtherThan (typeof (System.Web.UI.WebControls.Content), RootBuilder))
return false;
return true;
}