Using fnOpen with selector toggle - what am I doing wrong?

The following code works by clicking on the TR to extend another TR with any data. Great! But when I change the $('#example tbody tr').click() selector to something more specific in such as '#example tbody tr td.myclass a' the function fails. What am I missing. No doubt it has to do with the "this".

$(document).ready(function() {
  var oTable;
   
  // 'open' an information row when a row is clicked on
  $('#example tbody tr').click( function () {
    if ( oTable.fnIsOpen(this) ) {
      oTable.fnClose( this );
    } else {
      oTable.fnOpen( this, "Temporary row opened", "info_row" );
    }
  } );
   
  oTable = $('#example').dataTable();
} );