Bug 120218 Right click menu option to apply theme.
We should support the following right click menu. -- User right clicks int he report design layout area. -- The following menu items needs to be supported Theme --> Apply Theme -->Theme1 -->Theme2 ( similar to Apply style menu option )
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
DesignElementHandle dataSet = ( (ReportItemHandle) handle ).getDataSet( );
				if ( dataSet != null && !dataSetList.contains( dataSet ) )
				{
					dataSetList.add( dataSet );
				}
			}
			for ( Iterator itor = getDataSetList( handle.getContainer( ) ).iterator( ); itor.hasNext( ); )
			{
				DesignElementHandle dataSet = (DesignElementHandle) itor.next( );
				if ( !dataSetList.contains( dataSet ) )
				{
					dataSetList.add( dataSet );
				}
			}
		}
		return dataSetList;
	}
	/**
	 * Get definition of model property.
	 * 
	 * @param elementName
	 * @param propertyName
	 */
	public static IElementPropertyDefn getPropertyDefn( String elementName,
			String propertyName )
	{
		IElementDefn elementDefn = DesignEngine.getMetaDataDictionary( )
				.getElement( elementName );
		if ( elementDefn != null )
		{