0👍
After reading comment from @ssc-hrep3 I discovered that putting whole thing into
< transition > tag magically solves the problem.
<transition>
<div class="vuebar-element" v-bar v-if="tab==0">
<div>
tab 0
</div>
</div>
<div class="vuebar-element" v-bar v-if="tab==1">
<div>
tab 1
</div>
</div>
</transition>
Source:stackexchange.com