We register ourself as <code>UITabBarDelegate</code> in order to detect tab changes and
update also the selected sidebar tab.</p>

<div class="aside aside-warning">
          <p class="aside-title">Warning</p>
          You are not supposed to call this method directly.

        </div>

                      </div>
                      <div class="declaration">
                        <h4>Declaration</h4>
                        <div class="language">
                          <p class="aside-title">Swift<