drag drop - start dragging on mousedown event even cursor is over [cancel] element

drag drop - start dragging on mousedown event even cursor is over [cancel] element

Hi all,
 
My single draggable looks like,
<table>
<p><a>some link</a></p>
</table>
 
I have draggable elements (overall a table) which contains a hyperlink wrapped around in <P> tag and some other blank area. In load event, I initialized these draggable objects with [cancel:'p'] since I need user to be able to select the text of <a> element.
 
My requirement now is, if user holds mouse down for x seconds over hyperlink (<a>) then he/she should be able to drag the element (ie, table). Note that, in initialization event I set [cancel:'p'] due to my text selection requirement.
 
I have tried setting <some selector>.draggable("option", "cancel", ""); inside mousedown event of table. But, it doesn't work on first attempt of mousedown but on second/subsequent attempt it works.
 
Please advise.