<tr valign="top" class="second">
<td class="cmd">[...]</td>
<td>first last top bottom previous next both all current </td>
</tr>
</table>
first : first not top in sync
last : last not bottom in sync
both : ?
all : ?
current : ?
When the chain is to be ignored, one can append ":nocheck" to the keyword. There’s also a 'current' method.