Bug 145478 Unable "Select Value" in the Join data set's filter
Step to reproduce: 1.new a join data set(please use the attached file) 2.right click the dataset and click the Edit 3.go to the Filter pane and set a filer 4.click the list of Value1 Actual result: A warning pop up and cant select Value.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/data/ui/util/DataSetProvider.java
* 
	 * @param dataSet
	 * @return
	 * @throws BirtException
	 */
	public IBaseDataSetDesign createDataSetDesign( DataSetHandle dataSet )
			throws BirtException
	{
		DataSessionContext context = new DataSessionContext( DataSessionContext.MODE_DIRECT_PRESENTATION,
				dataSet.getModuleHandle( ) );
		DataRequestSession session = DataRequestSession.newSession( context );
		return session.getModelAdaptor( ).adaptDataSet( dataSet );
	}
	/**
	 * 
	 * @param dataSource
	 * @return
	 * @throws BirtException
	 */
	public IBaseDataSourceDesign createDataSourceDesign(
			DataSourceHandle dataSource ) throws BirtException
	{
		DataSessionContext context = new DataSessionContext( DataSessionContext.MODE_DIRECT_PRESENTATION,
				dataSource.getModuleHandle( ) );
		DataRequestSession session = DataRequestSession.newSession( context );
		return session.getModelAdaptor( ).adaptDataSource( dataSource );
	}
	
	/**
	 * Get cached data set item model. If none is cached, return null;