[tw5] How to get the top tiddler in view?

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.