Bug 312859 The list of operator for Chart filter does not provide 30 visible items
chart/org.eclipse.birt.chart.reportitem.ui/src/org/eclipse/birt/chart/reportitem/ui/dialogs/ChartCubeFilterConditionBuilder.java
catch ( BirtException e )
			{
				logger.log( Level.SEVERE, e.getMessage( ), e );
			}
		}
		return session;
	}
	protected synchronized void shutDownDteSession( )
	{
		if ( session != null )
		{
			session.shutdown( );
		}
	}
	/* (non-Javadoc)
	 * @see org.eclipse.birt.report.designer.ui.dialogs.FilterConditionBuilder#setColumnList(org.eclipse.birt.report.model.api.DesignElementHandle)
	 */
	protected void setColumnList( DesignElementHandle handle )
	{
		if ( handle instanceof ExtendedItemHandle )
		{
			try
			{
				fExprMap = getValidFilterExpressions( (ExtendedItemHandle) handle );
				columnList = new ArrayList<String>( fExprMap.keySet( ) );
				return;
			}
			catch ( ExtendedElementException e )
			{
				e.printStackTrace();