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
*            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.
	 */
	protected void checkBeforeRemove( DesignElement content )
			throws SemanticException
	{
		assert content != null;
		
		super.checkBeforeRemove( content );
		
		
		if ( !content.canDrop( module ) && !flag )
			throw ContentExceptionFactory
					.createContentException(
							focus,
							content,
							ContentException.DESIGN_EXCEPTION_STRUCTURE_CHANGE_FORBIDDEN );
		
		
		if ( hasDescendents( content ) )
		{
			throw ContentExceptionFactory.createContentException(
					new ContainerContext( content, focus.getSlotID( ) ),
					ContentException.DESIGN_EXCEPTION_HAS_DESCENDENTS );