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
setRefDate( getBinding( ), inUseDimsion );
		}
		if ( inUseDimsion )
		{
			recentButton.setEnabled( true );
		}
		else
		{
			recentButton.setEnabled( false );
		}
	}
	private boolean setRefDate( ComputedColumnHandle handle,
			boolean inUseDimsion )
	{
		String type = handle.getReferenceDateType( );
		if ( type == null )
			return false;
		if ( DesignChoiceConstants.REFERENCE_DATE_TYPE_TODAY.equals( type ) )
		{
			todayButton.setSelection( true );
			return true;
		}
		else if ( DesignChoiceConstants.REFERENCE_DATE_TYPE_FIXED_DATE.equals( type ) )
		{
			dateSelectionButton.setSelection( true );
			ExpressionHandle value = handle.getReferenceDateValue( );
			dateText.setText( value == null || value.getExpression( ) == null ? "" : (String) value.getExpression( ) ); 
			dateText.setData( ExpressionButtonUtil.EXPR_TYPE, value == null
					|| value.getType( ) == null ? ExpressionType.CONSTANT
					: (String) value.getType( ) );