Creating dialog using OJET

Question

I am trying to create OJET dialog. Though I am directly using code from cookbook I am getting error like "Uncaught (in promise) Error: You cannot apply bindings multiple times to the same element.".

Below is the code I am using .

<div id="dialogWrapper">
            <oj-dialog id="modalDialog1" dialog-title="Modal Dialog">
              <div slot="body">
                This is the dialog content.
                User can change dialog resize behavior, cancel behavior and drag behavior by setting attributes.
                Default attribute value depends on the theme.
              </div>
              <div slot="footer">
                <oj-button id="okButton" on-oj-action="[[close]]">OK
                </oj-button>
              </div>
            </oj-dialog>
            <oj-button id="buttonOpener" on-oj-action="[[open]]">
              Open Modal Dialog
            </oj-button>
            <div class="oj-sm-padding-4x-top" id='form-container'>
              <oj-form-layout direction="row" max-columns="1">
                <oj-input-text value="{{textVal1}}" label-hint="Address 1"></oj-input-text>
                <oj-input-text value="{{textVal2}}" label-hint="Address 2"></oj-input-text>
              </oj-form-layout>
            </div>
          </div>

Corresponding ViewModel code is

  require(["require", "exports", "knockout", "ojs/ojbootstrap", "ojs/ojknockout", "ojs/ojbutton", "ojs/ojdialog", "ojs/ojformlayout", "ojs/ojinputtext"], function (require, exports, ko, Bootstrap) {
      "use strict";
      
      class viewModel {
          constructor() {
              this.textVal1 = ko.observable("");
              this.textVal2 = ko.observable("");
          }
          close(event) {
              document.getElementById("modalDialog1").close();
          }
          open(event) {
              document.getElementById("modalDialog1").open();
          }
      }
      Bootstrap.whenDocumentReady().then(() => {
          ko.applyBindings(new viewModel(), document.getElementById("dialogWrapper"));
      });
  });

Can someone please help me to understand what is the mistake I am doing?