Bug 121498 When datasource/dataset deleted, the datasource/dataset property binding element haven't been deleted
When deleted the datasource/dataset, the datasource/dataset property binding element haven't been deleted. Expected result: This operation must be a transaction.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/ContentCommand.java
if ( slot.findPosn( e ) >= newPosn )
					return false;
				e = e.getExtendsElement( );
			}
		}
		return true;
	}
	/**
	 * Returns true if content in component slot of report design has
	 * descendants, otherwise false.
	 * 
	 * @param content
	 *            the content to handle
	 * @param fromSlotID
	 *            the slot that contains the element
	 * @return true if content has descendants, otherwise false.
	 */
	private boolean hasDescendents( DesignElement content, int fromSlotID )
	{
		return element instanceof ReportDesign
				&& fromSlotID == ReportDesign.COMPONENT_SLOT
				&& content.hasDerived( );
	}
	/**
	 * Does some transformation between template elements and report items or
	 * data sets. Virtually all elements must reside in a container. Containers
	 * are identified by a container ID.
	 *