title: Vuetify v-tabs-slider with v-if not working?
body: <p>I'm using Vuetify 0.16 with VueRouter and Vuex and noticing an issue using v-tabs with the v-tabs-slider with v-if vs v-show.</p>
  
  <pre><code>&lt;v-tabs icons grow light centered v-model="activeTab"&gt;
    &lt;v-toolbar&gt;
    ...
      &lt;v-tabs-bar v-show="showTabs" class="grey lighten-4" slot="extension"&gt;
        &lt;v-tabs-slider color="primary"&gt;&lt;/v-tabs-slider&gt;
        &lt;v-tabs-item v-for="tab in tabs" :key="tab.name" :id="tab.name" :to="tab.to" class="primary--text" router&gt;
          &lt;v-icon&gt;{{tab.icon}}&lt;/v-icon&gt;
          {{tab.name}}
        &lt;/v-tabs-item&gt;
      &lt;/v-tabs-bar&gt;
    &lt;/v-toolbar&gt;
  &lt;/v-tabs&gt;
  </code></pre>
  
  <p>activeTab, showTabs, and tabs are computed variables that reference getters in my vuex store.</p>
  
  <p>With the code above using v-show, everything works well, including the v-tabs-slider; however, when showTabs is false, the space for the tabs (heigh-wise) is still present. I want the toolbar to show no matter what, but I want to control the display of tabs depending on the route and taking up that space is not desirable (especially for mobile).</p>
  
  <p>If I change it to use v-if, the height issue is resolved and everything works except that the v-tabs-slider only works when the v-tabs-bar is initially loaded (when showTabs becomes true). When showTabs becomes false and then becomes true again, the v-tabs-slider no longer displays. The active tab's icon and text highlight correctly, but the v-tabs-slider does not highlight after it is unloaded and reloaded.</p>
  
  <pre><code>&lt;v-tabs icons grow light centered v-model="activeTab"&gt;
    &lt;v-toolbar&gt;
    ...
      &lt;v-tabs-bar v-if="showTabs" class="grey lighten-4" slot="extension"&gt;
        &lt;v-tabs-slider color="primary"&gt;&lt;/v-tabs-slider&gt;
        &lt;v-tabs-item v-for="tab in tabs" :key="tab.name" :id="tab.name" :to="tab.to" class="primary--text" router&gt;
          &lt;v-icon&gt;{{tab.icon}}&lt;/v-icon&gt;
          {{tab.name}}
        &lt;/v-tabs-item&gt;
      &lt;/v-tabs-bar&gt;
    &lt;/v-toolbar&gt;
  &lt;/v-tabs&gt;
  </code></pre>
  
  <p>I'm not sure if this is a bug or if I'm just not using this correctly...</p>
  
  <p>Does anyone know?</p>