Selected Primary menu items are not highlighted in default themes. If you wish to have this feature as on

http://csqa.info then

You will have to

1. Modify Style sheet
2. Modify page.tpl.php
3. Need attached images.

1. Add the following to your .css file. I am using bluemarine theme

#primary {
float: left;
width: 100%;
/*background: url("bg.gif") repeat-x bottom;*/
font-size: 118%;
line-height: normal;
background-color: transparent;
}

#primary ul {
margin: 0;
padding: 8px 8px 0;
list-style: none;
}

#primary a, #primary strong, #primary span {
background: url("images/norm_right.gif") no-repeat right top;
padding: 5px 15px 4px 6px;
font-weight: bold;
text-decoration: none;
color: black;
background-color: #E0FFFF;
display: block;
}

#primary li {
/* Change the following entry to make the tabs line up to the left */
float: left;
background: url("images/norm_left.gif") no-repeat left top;
padding: 0 0 0 9px;
margin: 0;
list-style-type: none;
background-color: Aqua;
}

#primary #current {
background-image: url("images/norm_left_on.gif");
border-bottom: none;
background-color: #EEE8AA;
}

#primary #current a {
background-image: url("images/norm_right_on.gif") ;
font-weight: bold;
padding-bottom: 5px;
border-bottom: none;
color: #666633;

}

2. Comment & add the following to your page.tpl.php. Snippet from Bluemarine theme

<?php if (count($primary_links)) : ?>

<?php foreach ($primary_links as $link): ?>
<?php $class = ""; ?>

<?php if ( stristr($link, 'active') ) : ?>
<?php $class = 'id="current"'; ?>
<?php endif; ?>

• ><?php print $link?>

<?php endforeach; ?>

<?php endif; ?>