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
validate( );
		hasInitDialog = true;
		composite.getShell( ).pack( );
	}
	private void initReferenceDate( )
	{
		String dimensionName = getTimeDimsionName( );
		boolean inUseDimsion = isUseDimension( dimensionName );
		if ( getBinding( ) == null ) 
		{
			ExtendedItemHandle handle = (ExtendedItemHandle) getBindingHolder( );
			List<ComputedColumnHandle> dimensionHandle = new ArrayList( );
			for ( Iterator<ComputedColumnHandle> iter = handle.columnBindingsIterator( ); iter.hasNext( ); )
			{
				ComputedColumnHandle cHandle = iter.next( );
				if ( cHandle.getTimeDimension( ) != null
						&& !cHandle.getTimeDimension( ).equals( EMPTY_STRING ) )
				{
					dimensionHandle.add( 0, cHandle );
				}
			}
			if ( 0 == dimensionHandle.size( )
					|| !setRefDate( dimensionHandle.get( 0 ), inUseDimsion ) )
			{
				todayButton.setSelection( true );
			}
		}
		else
		
		{