/Possum
<div class="pas"><a class="sublinks" href="http://demo.boonex.com/Possum">Profile</a></div>
templates/base/scripts/BxBaseMenu.php:277
$iItemID == $this->aMenuInfo['currentCustom']
(-1 == 777) isn't equal for this menu item, hence it doesn't get the 'act' class.
In Account Home (/member.php) however it is active as expected:
<div class="act">Account Home</div>