Bug 121287 Post BIRT M3 build: Edit Group Dialog does not present expression builder for Group On
In Edit Group dialog, there is no expression builder for the Group On field. In order to support multi-pass aggregation, the expression builder is needed to specify an expression to group on.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/GroupDialog.java
{
			nameEditor.setText( inputGroup.getName( ) );
		}
		columnList = DataSetManager.getCurrentInstance( )
				.getColumns( dataSetList );
		Iterator itor = columnList.iterator( );
		while ( itor.hasNext( ) )
		{
			keyChooser.add( ( (DataSetItemModel) itor.next( ) ).getDisplayName( ) );
		}
		String groupKey = inputGroup.getKeyExpr( );
		int index = -1;
		if ( groupKey != null )
		{
			for ( int i = 0; i < columnList.size( ); i++ )
			{
				if ( groupKey.equals( DEUtil.getExpression( columnList.get( i ) ) ) )
				{
					index = i;
					break;
				}
			}
			if ( index != -1 )
			{
				keyChooser.select( index );
			}
		}
		index = getIntervalTypeIndex( inputGroup.getInterval( ) );
		intervalType.select( index );
		if ( index == 0 )