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
{
				AggregationCellHandle cellHandle = (AggregationCellHandle) container;
				if ( cellHandle.getAggregationOnRow( ) != null )
				{
					aggstr += cellHandle.getAggregationOnRow( ).getFullName( );
					if ( cellHandle.getAggregationOnColumn( ) != null )
					{
						aggstr += ","; 
					}
				}
				if ( cellHandle.getAggregationOnColumn( ) != null )
				{
					aggstr += cellHandle.getAggregationOnColumn( )
							.getFullName( );
				}
			}
			String[] strs = aggstr.split( "," );
			String temAddOns = "";
			if ( strs != null && strs.length > 1 )
			{
				for ( int i = strs.length - 1; i >= 0; i-- )
				{
					temAddOns = temAddOns + strs[i];
					if ( i != 0 )
					{
						temAddOns = temAddOns + ",";
					}
				}
			}
			for ( int j = 0; j < aggOns.length; j++ )