Tab Index Highlight on focus

Question

Hi Guys,

I am facing a strange problem, I have a div quicklaunch in master page. When I press Tab then it traverse across all controls in page ( default behaviour).Now the problem Tab movement is not displaying (dotted lines) when it goes to Quick Launch panel.. whats the problem or Any easy solution to highlight when it focus....Problem is default behaviour is not working..any idea..?
 
Div structure...
<div>
<ul>
if(condition)
<li>abc</li>
if(condition)
<li>abcd</li>
</ul>
</div>

Advanced thanks......