Bug 141950 Selection of select value in data set filter is error
Details: Selection of select value in data set filter is error Step: 1.New a report design. 2.Create a sample datasource and dataset. 3.Switch to filter. 4.Select a value in expression. 5.Drop the list of the value1 and select <select value...> Actual result: No value is appear and pop up an error. It said that "An expression has not been set"
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/data/ui/util/DataSetProvider.java
updateModel( dataSet, dsItemModel );
		htColumns.put( dataSet, dsItemModel );
	}
	/**
	 * @param dataSet
	 * @return
	 * @throws BirtException
	 */
	public IQueryResults execute( DataSetHandle dataSet ) throws BirtException
	{
		return execute( dataSet, true, true, -1 );
	}
	
	/**
	 * execute query definition 
	 * @param dataSet
	 * @param useColumnHints
	 * @param rowsToReturn
	 * @return
	 * @throws BirtException
	 */
	public IQueryResults execute( DataSetHandle dataSet,
			boolean useColumnHints, boolean useFilters, int rowsToReturn )
			throws BirtException
	{
		
		DataSessionContext context = new DataSessionContext( DataSessionContext.MODE_DIRECT_PRESENTATION,
				dataSet.getModuleHandle( ) );
		DataRequestSession session = DataRequestSession.newSession( context );
		IBaseDataSetDesign dataSetDesign = session.getModelAdaptor( )