Bug 121864 Report element can't be deleted
Description: Report element can't be deleted Steps to reproduce: 1.Open the attached design file 2.Delete the table/parameters/dataset/datasource Expected result: The element can be deleted Actual result: They can't be deleted
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/ContentCommand.java
*            the element to remove
	 * @param slotID
	 *            the slot from which to remove the content
	 * @param unresolveReference
	 *            status whether to un-resolve the references
	 * @throws SemanticException
	 *             if this content cannot be removed from container.
	 */
	public void remove( DesignElement content, int slotID,
			boolean unresolveReference ) throws SemanticException
	{
		doRemove( content, slotID, unresolveReference, false );
	}
	/**
	 * @see #remove(DesignElement, int, boolean)
	 * @param content
	 *            the element to remove
	 * @param slotID
	 *            the slot from which to remove the content
	 * @param unresolveReference
	 *            status whether to un-resolve the references
	 * @param flag
	 *            Use the flag to indicate whether this method is do with the
	 *            element itself or do with its contents.
	 * @throws SemanticException
	 *             if this content cannot be removed from container.
	 */
	private void doRemove( DesignElement content, int slotID,
			boolean unresolveReference, boolean flag ) throws SemanticException
	{