* @param id the id of the element to be found
* @return the element with the given id, or <code>null</code> if none is found
*/
public com.google.gwt.user.client.Element getElementById(String id) {
Element elem = isAttached() ? Document.get().getElementById(id) : attachToDomAndGetElement(id);
return elem.cast();
}
/**
* Performs a {@link DOM#getElementById(String)} after attaching the panel's
* element into a hidden DIV in the document's body. Attachment is necessary