public void DeleteElements( 
   Func<Element,bool> predicate
)

{
  //Note: Must be on QueuedTask.Run
  var elementsToRemove = layout.GetSelectedElements();
  layout.DeleteElements(elementsToRemove);
}

{
  //Delete an element or elements on a layout.
  //Note: Must be on QueuedTask.Run

  //Delete a specific element on a layout
  //Find a single specific element
  Element rect = layout.FindElement("Rectangle") as Element;
  layout.DeleteElement(rect);

  //Or delete a group of elements using a filter
  layout.DeleteElements(item => item.Name.Contains("Clone"));

  //Or delete all elements on a layout
  layout.DeleteElements(item => true);
}