V-data-table not registering template code

I have seen numerous examples using template inside of v-data-table to allow customizing it. I am trying to build some inline filter functionality with v-menu but I am not even able to get the template to register its changes. Just this simple example adding an icon next to the header does not seem to do anything. Its as if template has no effect and currently no errors are shown in console and the data is loaded as normal.

                                <v-data-table :headers="headersResults"
                                          :items="results"
                                          :search="search"
                                          height="inherit"
                                          @@click:row="goToItem">
                                <template v-slot:headers="props">
                                    <tr>
                                        <th v-for="(header,i) in props.headers"
                                            :key="i">
                                            {{ header.text }}
                                            <v-icon small>arrow_upward</v-icon>
                                            <v-btn icon color="grey lighten-2">
                                                <v-icon class='no-rotate' @@click.stop small color="pink">{{ mdi-magnify }}</v-icon>
                                            </v-btn>
                                        </th>
                                    </tr>
                                </template>
                            </v-data-table>