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
{
				this.newBinding = StructureFactory.newComputedColumn( getBindingHolder( ),
						DEFAULT_TIMEPERIOD_NAME );
			}
			else
			{
				this.newBinding = StructureFactory.newComputedColumn( getBindingHolder( ),
						isAggregate( ) ? DEFAULT_AGGREGATION_NAME
								: DEFAULT_ITEM_NAME );
			}
			setName( this.newBinding.getName( ) );
		}
		else
		{
			setName( getBinding( ).getName( ) );
			setDisplayName( getBinding( ).getDisplayName( ) );
			setDisplayNameID( getBinding( ).getDisplayNameID( ) );
			if ( getBinding( ).getDataType( ) != null )
				if ( DATA_TYPE_CHOICE_SET.findChoice( getBinding( ).getDataType( ) ) != null )
					setTypeSelect( DATA_TYPE_CHOICE_SET.findChoice( getBinding( ).getDataType( ) )
							.getDisplayName( ) );
				else
					cmbType.setText( "" ); 
			if ( getBinding( ).getExpression( ) != null )
				setDataFieldExpression( getBinding( ) );
		}
		if ( this.getBinding( ) != null )
		{
			this.txtName.setEnabled( false );
		}