message: Fix functional tests with vue
diff: <input
  type="button"
  :value="survey.pagePrevText"
  - v-show="!survey.isFirstPage && survey.isShowPrevButton"
  + v-show="showPrevBtn"
  :class="survey.cssNavigationPrev"
  @mousedown="buttonMouseDown"
  @click="prevPage"
  <input
  type="button"
  :value="survey.pageNextText"
  - v-show="!survey.isLastPage"
  + v-show="showNextBtn"
  :class="survey.cssNavigationNext"
  @mousedown="nextButtonMouseDown"
  @click="nextPage"
  @@ -46,6 +46,9 @@ import { BaseVue } from "./base";
  @Component
  export class Navigation extends BaseVue {
  private mouseDownPage: PageModel;
  + showPrevBtn: boolean = true;
  + showNextBtn: boolean = true;
  + showCompleteBtn: boolean = true;
  @Prop() survey: SurveyModel;
  @Prop() css: any;
  protected getModel(): Base {
  @@ -54,6 +57,18 @@ export class Navigation extends BaseVue {
  @Watch("survey")
  onPropertyChanged(value: string, oldValue: string) {
  this.onCreated();
  + this.updateShowButtons();
  + }
  + protected onMounted() {
  + this.survey.onCurrentPageChanged.add((sender, options) => {
  + this.updateShowButtons();
  + });
  + this.updateShowButtons();
  + }
  + private updateShowButtons() {
  + this.showPrevBtn = !this.survey.isFirstPage && this.survey.isShowPrevButton;
  + this.showNextBtn = !this.survey.isLastPage;
  + this.showCompleteBtn = this.survey.isLastPage;
  }
  nextButtonMouseDown() {
  this.mouseDownPage = this.survey.currentPage;
  