title: Items in Vuetify list subgroup not stacking vertically
body: <p>I've taken over a Vue (2.5.22) app with Vuetify (1.4.3), and the app has a left nav that uses <code>v-list</code> and <code>v-list-group</code> elements:</p>
  
  <pre><code>&lt;template&gt;
    &lt;v-list dark class="ap-sidebar-applist"&gt;
      &lt;v-list-group
        class="ap-sidebar-group"
        v-for="(item, i) in items"
        :key="i"
        :prepend-icon="item.icon"
        :value="item.visible"
        @click="onClick(item)"
      &gt;
        &lt;v-list-tile slot="activator"&gt;
          &lt;v-list-tile-title&gt;{{ item.title }}&lt;/v-list-tile-title&gt;
        &lt;/v-list-tile&gt;
  
        &lt;v-list-group
          v-if="item.children"
          sub-group
          no-action
          class="ap-sidebar-subgroup"
        &gt;
          &lt;v-list-tile slot="activator"
            v-for="(subMenu, j) in item.children"
            :key="j"
            @click="onClick(subMenu, true)"
          &gt;
            &lt;v-list-tile-action&gt;
              &lt;v-icon&gt;{{ subMenu.icon }}&lt;/v-icon&gt;
            &lt;/v-list-tile-action&gt;
            &lt;v-list-tile-title&gt;{{ subMenu.title }}&lt;/v-list-tile-title&gt;
          &lt;/v-list-tile&gt;
        &lt;/v-list-group&gt;
  
      &lt;/v-list-group&gt;
    &lt;/v-list&gt;
  &lt;/template&gt;
  </code></pre>
  
  <pre><code>export default {
    name: 'TheLeftSidebarAppList',
    props: {
      visible: Boolean,
    },
    data: () =&gt; ({
      items: [
        {
          icon: 'group',
          title: 'Users',
          routeTo: 'UserEdit',
          method: null,
          superOnly: false,
          taCanView: true,
          visible: true,
          children: [
            {
              icon: 'send',
              title: 'Send Quick Alert',
              method: 1,
            },
          ],
        },
        {
          icon: 'domain',
          title: 'Tenants',
          routeTo: 'TenantEdit',
          method: null,
          superOnly: false,
          taCanView: true,
          visible: false,
          children: [
            {
              icon: 'fingerprint',
              title: 'Manage Biometrics',
              method: 1,
            },
            {
              icon: 'email',
              title: 'Manage Templates',
              method: 1,
            },
          ],
        },
        {
          icon: 'assessment',
          title: 'Reports',
          routeTo: 'WorkspaceReports',
          method: null,
          superOnly: false,
          taCanView: true,
          visible: false,
        },
        {
          icon: 'settings',
          title: 'Server Configuration',
          routeTo: null,
          method: 2,
          superOnly: false,
          taCanView: false,
          visible: false,
        },
        {
          icon: 'trending_up',
          title: 'Performance',
          routeTo: 'WorkspacePerformance',
          method: null,
          superOnly: true,
          taCanView: true,
          visible: false,
        },
      ],
    }),
  }
  </code></pre>
  
  <p>I want to add two items under the <code>Tenants</code> item by adding a <code>children</code> array in the data:</p>
  
  <pre><code>      {
          icon: 'domain',
          title: 'Tenants',
          routeTo: 'TenantEdit',
          method: null,
          superOnly: false,
          taCanView: true,
          visible: false,
          children: [
            {
              icon: 'fingerprint',
              title: 'Manage Biometrics',
              method: 1,
            },
            {
              icon: 'email',
              title: 'Manage Templates',
              method: 1,
            },
          ],
        },
  </code></pre>
  
  <p>but when it is displayed, the children items are displayed horizontally, instead of being stacked vertically:</p>
  
  <p><a href="https://i.stack.imgur.com/iD0Qx.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/iD0Qx.png" alt="enter image description here"></a></p>
  
  <p>From everything I've seen, they should stack vertically, but they don't. What do I need to do to get them to be stacked vertically?</p>
  
  <p><strong>UPDATE:</strong> This component is included in a parent component that wraps this in a <code>&lt;v-navigation-drawer&gt;</code> component:</p>
  
  <pre><code>&lt;template&gt;
    &lt;v-navigation-drawer
      v-model="visible"
      fixed
      app
      dark
      class="primary"
    &gt;
      &lt;v-toolbar flat class="ap-img-toolbar"&gt;
        &lt;v-list class="pa-0"&gt;
          &lt;v-list-tile&gt;
            &lt;v-list-tile-action&gt;
              &lt;img src="/images/LogoSmall.png"&gt;
  
            &lt;/v-list-tile-action&gt;
          &lt;/v-list-tile&gt;
        &lt;/v-list&gt;
      &lt;/v-toolbar&gt;
  
      &lt;TheLeftSidebarAppList /&gt;
  
    &lt;/v-navigation-drawer&gt;
  &lt;/template&gt;
  </code></pre>