Attach InfoWindow to Polyline

[kieranwild]

I can't seem to attached an InfoWindow to a Polyline:

<template>
  <section class="section">
      <gmap-map
        v-bind:center="center"
        v-bind:zoom="12"
        style="width: 800px; height:500px">
          <gmap-polyline 
           v-bind:path.sync="path"  
           v-bind:options="{ strokeColor:'#008000',  suppressInfoWindows: false}">
             <gmap-info-window>Test InfoWindow text ! </gmap-info-window>
           </gmap-polyline>
      </gmap-map>
  </section>
</template>
<script>
  export default {
    data () {
      return { 
        center: {lat: 55.915655, lng: -4.744502},
        path: [
          {lat: 55.9352001, lng: -4.7766924 },
          {lat: 55.9358131, lng: -4.7770143 },
          {lat: 55.9361256, lng: -4.7767353 },
          {lat: 55.9366784, lng: -4.7739458 },
          {lat: 55.9371231, lng: -4.7731304 },
          {lat: 55.9377481, lng: -4.7727227 }
          ]
          }
      }
    }  
</script>

The Info-Window is not showing up on the map or in Chrome Vue dev tools. I have tried it just as info-window . I am missing something obvious?