Bug 122306 TOC on group won't be displayed
Description: TOC on group won't be displayed Steps to reproduce: 1.Add a sample datasource and a data with table "CUSTOMERS" 2.Add a table binding with data set 3.Add a group on the table and set the toc expression to "Group" 4.Preview in HTML Expected result: TOC "Group" will be displayed on the TOC pane Actual result: Nothing in the TOC pane
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/data/dte/ReportQueryBuilder.java
* A helper function for removing a query from query stack
		 */
		protected void popQuery( )
		{
			assert !queryStack.isEmpty( );
			queryStack.removeLast( );
		}
		/**
		 * add expression to the expression collection on top of the expressions
		 * stack
		 * 
		 * @param expr
		 *            expression to be added
		 */
		protected void addExpression( IBaseExpression expr )
		{
			
			
			if ( expr != null && expressions != null )
				expressions.add( expr );
		}
		/**
		 * @return topmost element on query stack
		 */
		protected IBaseTransform getTransform( )
		{
			if ( queryStack.isEmpty( ) )
				return null;
			return (IBaseTransform) queryStack.getLast( );
		}