How to using v-slot in v-calendar and not replace the original template

Question

I want to add a checkbox on a v-calendar event.

I'm new to Vuetify.

Here is my code:

<v-calendar
    v-model="value"
    :weekdays="weekday"
    :type="type"
    :events="events"
    @change="getEvents"
>
    <template v-slot:event="{ event }">
        <input .../>
    </template>
</v-calendar>

code online

Now the problem is, it will replace the original template which are name and time, how should I keep them all?