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
int itemIndex = getItemIndex( names, name );
				if ( itemIndex >= 0 )
				{
					calculationType.select( itemIndex );
				}
				else
				{
					calculationType.select( 0 );
				}
			}
			handleCalculationSelectEvent( );
			ITimeFunction function = getTimeFunctionByIndex( calculationType.getSelectionIndex( ) );
			List<IArgumentInfo> infos = function.getArguments( );
			for ( int i = 0; i < infos.size( ); i++ )
			{
				String argName = infos.get( i ).getName( );
				String argValue = calculationParamsValueMap.get( argName );
				if ( calculationParamsMap.containsKey( argName ) )
				{
					if ( getArgumentValue( getBinding( ), argName ) != null )
					{
						Control control = calculationParamsMap.get( argName );
						ExpressionHandle obj = (ExpressionHandle) getArgumentValue( getBinding( ),
								argName );
						if ( infos.get( i ).getPeriodChoices( ) == null
								|| infos.get( i ).getPeriodChoices( ).isEmpty( ) )
						{
							initExpressionButtonControl( control, obj );
						}
						else