code: function _toggleBoundaryToggle () {
          var somethingEntered = false;
  
          $('input[type="number"]').each(function () {
              if (parseInt(this.value, 10) !== 0) {
                  somethingEntered = true;
              }
          });
  
          if (somethingEntered) {
              $showBoundsCheck.parent().slideDown();
          }
          else {
              $showBoundsCheck.parent().slideUp();
          }
      }
docs: /////// GUI // /////// Display or hide the "show boundaries" check box if any values are set (non-zero)