openproject/public/templates/components/activity_comment.html

<div class="activity-comment" ng-if="canAddComment">
  <form name="commentForm">
    <label>
      <h3>{{ title }}</h3>
      <textarea id="add-comment-text"
                class="add-comment-text"
                name="add_comment_text"
                ng-model="activity.comment"
                required
                placeholder="Add your comments here">
      </textarea>
      <button class="button"
              ng-click="createComment()"
              ng-disabled="commentForm.$invalid"><i class="icon-yes icon-left"></i>{{ buttonTitle }}
      </button>
      <button class="button" ng-disabled="commentForm.$invalid" ng-click="clearComment()">
        <i class="icon-close icon-left"></i>{{ buttonCancel }}</button>
    </label>
  </form>
</div>