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
import org.eclipse.birt.report.model.core.ContainerSlot;
import org.eclipse.birt.report.model.core.DesignElement;
import org.eclipse.birt.report.model.core.Module;
import org.eclipse.birt.report.model.core.ReferenceableElement;
import org.eclipse.birt.report.model.core.StyledElement;
import org.eclipse.birt.report.model.elements.ReportDesign;
import org.eclipse.birt.report.model.elements.TemplateParameterDefinition;
import org.eclipse.birt.report.model.i18n.MessageConstants;
import org.eclipse.birt.report.model.i18n.ModelMessages;
import org.eclipse.birt.report.model.metadata.ElementDefn;
import org.eclipse.birt.report.model.metadata.ElementPropertyDefn;
import org.eclipse.birt.report.model.metadata.ElementRefValue;
import org.eclipse.birt.report.model.metadata.PropertyDefn;
import org.eclipse.birt.report.model.metadata.PropertyType;
import org.eclipse.birt.report.model.metadata.SlotDefn;
import org.eclipse.birt.report.model.metadata.StructRefValue;
/**
 * This class adds, deletes and moves content elements. Adding a content element
 * to a container is the only way to add a new element to the design. Similarly,
 * removing an element from its container is the only way to delete an element
 * from the design.
 * <p>
 * Note: be sure to use the move operation if your intent is to move an element
 * from one place to another. Do not use a drop followed by an add. The move
 * command verifies that the move can be done before starting the action. If you
 * instead do a drop followed by an add, you'll end up with the element deleted
 * if it cannot be added into its new location.
 * 
 */
public class ContentCommand extends AbstractElementCommand