It's possible with a very simple code edit:
Open the file: library/XenForo/Model/Session.php
Find:
	
	
	
		PHP:
	
	
		public function getSessionActivityQuickList(array $viewingUser, array $conditions = array(), array $forceInclude = null)
	 
 
Shortly below that you'll see:
	
	
	
		PHP:
	
	
		        $fetchOptions = array(
            'join' => self::FETCH_USER,
            'order' => 'view_date'
        );
	 
 
Change 'view_date' to 'username'.