title: v-btn of v-dialog disappears when adding v-bind to attribute
body: <p>With Vuetify, I created a dialog in which I want to bind placeholders of my different <code>v-text-field</code>. </p>
  
  <pre><code>&lt;template&gt;
    &lt;v-row justify="center"&gt;
      &lt;v-dialog v-model="dialog" persistent max-width="600px"&gt;
        &lt;template v-slot:activator="{ on }"&gt;
          &lt;v-btn text icon dark v-on="on" color="black"&gt;
            &lt;v-icon&gt;mdi-pencil-outline&lt;/v-icon&gt;
          &lt;/v-btn&gt;
        &lt;/template&gt;
        &lt;v-card&gt;
          &lt;v-card-title&gt;
            &lt;span class="headline"&gt;Edit profile&lt;/span&gt;
          &lt;/v-card-title&gt;
          &lt;v-card-text&gt;
            &lt;v-container&gt;
              &lt;v-row&gt;
                &lt;v-col cols="12" sm="6" md="4"&gt;
                  &lt;v-text-field v-model="f_name" :label="getName()" required&gt;&lt;/v-text-field&gt;
                &lt;/v-col&gt;
              &lt;/v-row&gt;
            &lt;/v-container&gt;
          &lt;/v-card-text&gt;
        &lt;/v-card&gt;
      &lt;/v-dialog&gt;
    &lt;/v-row&gt;
  &lt;/template&gt;
  
  &lt;script&gt;
    export default {
        name: "edit_form_personal",
        data() {
            return {
              dialog: false,
              f_name: '',
              l_name: '',
              email: '',
              phone: ''
            }
        },
        methods: {
            getName() {
              return 'joe'
            }
        },
    }
  &lt;/script&gt;
  </code></pre>
  
  <p>I am using <code>getName()</code> to bind 'joe' inside my form. 
  The issue is that when I change</p>
  
  <p><code>&lt;v-text-field v-model="f_name" label="First Name" required&gt;&lt;/v-text-field&gt;</code></p>
  
  <p>to :</p>
  
  <p><code>&lt;v-text-field v-model="f_name" :label="getName()" required&gt;&lt;/v-text-field&gt;</code></p>
  
  <p>the <code>&lt;v-btn&gt;</code> disappears as if the <code>v-dialog</code> was broken.</p>