<div class="host" tabindex="-1" ng-click="eventHandlers.host.click()" ti-transclude-append>
  <div class="tags">
    <ul class="tag-list">
      <li class="tag-item"
          ng-repeat="tag in tagList.items track by track(tag)"
          tooltip="{{getDisplayText(tag)}}"
          tooltip-placement="bottom"
          tooltip-trigger="mouseenter"
          ng-class="{ selected: tag == tagList.selected }">
        <span ng-bind="getDisplayText(tag)"></span>
        <button class="btn btn-link remove-button"
                type="button"
                ng-click="tagList.remove($index)"
                ng-bind="options.removeTagSymbol"
                tabindex="0"></button>
      </li>
    </ul>
    <input class="input"
           ng-model="newTag.text"
           ng-change="eventHandlers.input.change(newTag.text)"
           ng-keydown="eventHandlers.input.keydown($event)"
           ng-trim="false"
           ng-class="{'invalid-tag': newTag.invalid}"
           ng-hide="tagList.items.length >= options.limit"
           ti-bind-attrs="{type: options.type, placeholder: options.placeholder, tabindex: options.tabindex, spellcheck: options.spellcheck}"
           ti-autosize>
  </div>
</div>

<div class="host" tabindex="-1" ng-click="eventHandlers.host.click()" ti-transclude-append>
  <div class="tags">
    <ul class="tag-list">
      <li class="tag-item"
          ng-repeat="tag in tagList.items track by track(tag)"
          tooltip="{{getDisplayText(tag)}}"
          tooltip-placement="bottom"
          tooltip-trigger="mouseenter"
          ng-class="{ selected: tag == tagList.selected }">
        <span ng-bind="getDisplayText(tag)"></span>
        <button class="btn btn-link remove-button"
                type="button"
                ng-click="tagList.remove($index)"
                ng-bind="options.removeTagSymbol"
                tabindex="{{options.tabindex}}"></button>
      </li>
    </ul>
    <input class="input"
           ng-model="newTag.text"
           ng-change="eventHandlers.input.change(newTag.text)"
           ng-keydown="eventHandlers.input.keydown($event)"
           ng-trim="false"
           ng-class="{'invalid-tag': newTag.invalid}"
           ng-hide="tagList.items.length >= options.limit"
           ti-bind-attrs="{type: options.type, placeholder: options.placeholder, tabindex: options.tabindex, spellcheck: options.spellcheck}"
           ti-autosize>
  </div>
</div>

Modify tabindex of remove button
Modify tabindex of remove button
