How to get the top tiddler in view?

[imleg...@gmail.com]

I use a shortcut to edit the top tiddler . 

Content is : 

```

<$navigator story="$:/StoryList" history="$:/HistoryList">

<$action-sendmessage $message="tm-edit-tiddler" $param={{{ [list[$:/StoryList]first[]] }}}/>

</$navigator>

```

But now I want to edit the top tiddler in view, that means when you scroll down a little. The top tiddler in you sight has not to be the first one you open. How to make it? 

I google for get top tiddler in view but can't solve it.