Bug 188829 Move the item ,the trans of the model don't close.
1:New report design. 2:Add a Embedded image. 3:Add another imge , then drag the second imge to the first position. 4:Change the size of the first image. Expected: Image change the size. Now: Image size don't change.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/ContentCommand.java
* <li>The elements that use this style.
	 * <li>The elements that this content contains.
	 * <li>The name space that contains this content.
	 * </ul>
	 * 
	 * @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
	 * @throws SemanticException
	 *             if this content cannot be removed from container.
	 */
	public void remove( DesignElement content, boolean unresolveReference )
			throws SemanticException
	{
		this.unresolveReference = unresolveReference;
		this.flag = false;
		super.remove( content );
	}
	/**
	 * Removes an item from its container. This is equivalent to deleting the
	 * element from the design. Because the element is being deleted, we must
	 * clean up all references to or from the element. References include:
	 * <p>
	 * <ul>
	 * <li>The elements that this content extends.
	 * <li>The elements that extend this content.
	 * <li>The style that this content uses.