dtop]=null;
              last_pans[addtop]=null;

              var cell = row.insertCell(0);
              cell.className = "tracklbl";
              cell.onmousedown = inspect_track_handler(addtop);

              cell.appendChild(document.createElement('div'));
              var div=document.createElement('div');
              div.className = "trackinfo";
              cell.appendChild(div);

              cell = row.insertCell(1);
              cell.className = "trackbut";
              if (addtop > 0)