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
isStatic = false;
				initCalculationTypeCombo( getTimeDimsionName( ) );
			}
		}
		modifyDialogContent( );
		validate( );
	}
	private String getDateHintText( )
	{
		return ExpressionType.CONSTANT.equalsIgnoreCase( button.getExpressionHelper( )
				.getExpressionType( ) ) ? Messages.getString( "CrosstabBindingDialogHelper.thisdate.example.label.constant" )
				: Messages.getString( "CrosstabBindingDialogHelper.thisdate.example.label" );
	}
	private Listener changeExprTypeListener = new Listener( ) {
		public void handleEvent( Event e )
		{
			if ( e.widget instanceof MenuButton )
			{
				dateFormatLbl.setText( getDateHintText( ) );
				composite.getShell().pack(true);
			}
		}
	};
	private void handleTimeDimensionSelectEvent( )
	{
		String dimensionName = getTimeDimsionName( );
		initCalculationTypeCombo( dimensionName );
		boolean inUseDimsion = isUseDimension( dimensionName );
		if ( inUseDimsion )
		{