Bug 148626 [Regression]Can't fetch value from the filter of table/chart which inherites data from container
Steps: 1. create a table and bind a dataset in it 2. create another table/chart in the table detail/table group header 3. switch to the Filter tab in property editor 4. create a filter and select value in "<select value...>" combo 5. an error popuped up, "The expression value can't be retrieved"
chart/org.eclipse.birt.chart.reportitem.ui/src/org/eclipse/birt/chart/reportitem/ui/ReportDataServiceProvider.java
return itemHandle.getStyle( ).getName( );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.chart.ui.interfaces.IDataServiceProvider#setStyle(java.lang.String)
	 */
	public void setStyle( String styleName )
	{
		try
		{
			if ( styleName == null )
			{
				itemHandle.setStyle( null );
			}
			else
			{
				itemHandle.setStyle( getStyle( styleName ) );
			}
		}
		catch ( SemanticException e )
		{
			ChartWizard.showException( e.getLocalizedMessage( ) );
		}
	}
	private SharedStyleHandle getStyle( String styleName )
	{
		return getReportDesignHandle( ).findStyle( styleName );
	}
	public final Object[] getDataForColumns( String[] sExpressions,