Bug 390669 [Accessibility]Press 'Tab' doesn't focus on the next report item when adding relative period aggregation.
xtab/org.eclipse.birt.report.item.crosstab.ui/src/org/eclipse/birt/report/item/crosstab/internal/ui/dialogs/CrosstabBindingDialogHelper.java
for ( int j = 0; j < levels; j++ )
				{
					LevelViewHandle level = dimension.getLevel( j );
					if ( level.getCubeLevel( ) != null )
					{
						levelList.add( level.getCubeLevel( ).getFullName( ) );
					}
				}
			}
		}
		return levelList;
	}
	private void initFilter( )
	{
		ExpressionButtonUtil.initExpressionButtonControl( txtFilter,
				binding,
				ComputedColumn.FILTER_MEMBER );
	}
	private void initFunction( )
	{
		cmbFunction.setItems( getFunctionDisplayNames( ) );
		
		if ( binding == null )
		{
			cmbFunction.select( 0 );
			handleFunctionSelectEvent( );
			return;
		}
		try
		{