anchor.diff:            <div class="panel panel-default">
               <div class="panel-heading">
                 <h4 class="panel-title">
  -                <a data-toggle="collapse" data-parent="accordion" href="collapse-two">
  +                <a data-toggle="collapse" data-parent="#accordion" href="#collapse-two">
                     Topic #2
                   </a>
                 </h4>
  
positive.code:           <div class="panel panel-default">
              <div class="panel-heading">
                <h4 class="panel-title">
                  <a data-toggle="collapse" data-parent="accordion" href="collapse-one">
                    Topic #1
                  </a>
                </h4>
  
negative.code:           <div class="panel panel-default">
              <div class="panel-heading">
                <h4 class="panel-title">
                  <a data-toggle="collapse" data-parent="#accordion" href="#collapse-three">
                    Topic #3
                  </a>
                </h4>
  