Bug 121352 The data set binding property cannot be retrieved in report preview layout
In report preview page, the datasource/dataset property binding lists cannot be retrieved. The dataset binding can not work correctly in layout preview because it's value cannot get from the binding list. But in the data set edit page, the binding value can be got. You can refer to the attachment.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Module.java
*/
	public void dropElementID( DesignElement element )
	{
		if ( idMap == null )
			return;
		assert element.getID( ) > 0;
		Long idObj = new Long( element.getID( ) );
		assert idMap.containsKey( idObj );
		idMap.remove( idObj );
	}
	/**
	 * Looks up an element given an element ID. Returns null if no element
	 * exists with the given ID. Also returns null if IDs are not enabled. Note:
	 * this method will not find an element that has previously been deleted
	 * from the module, even if that element still exists in memory in
	 * anticipation of issuing an undo of the delete. That is, only valid
	 * elements can be found.
	 * 
	 * @param id
	 *            The id of the element to find.
	 * @return The element itself, or null if the element can't be found or if
	 *         IDs are not enabled.
	 */
	public DesignElement getElementByID( long id )
	{
		if ( idMap == null )
			return null;
		return (DesignElement) idMap.get( new Long( id ) );
	}
	/**