Vertical checkbox top-right corner is not rounded

[clytras]

The top right conrner is not rounded because both btn-group and btn-group-vertical class are applied:

<div is="0" class="btn-group btn-group-vertical m-b" tabindex="0">
 <a is="0" class="btn active btn-danger">No</a>
 <a is="1" class="btn btn-default">Yes</a>
</div>

It displays just fine if I remove the btn-group class from the div:

<div is="0" class="btn-group-vertical m-b" tabindex="0">
 <a is="0" class="btn active btn-danger">No</a>
 <a is="1" class="btn btn-default">Yes</a>
</div>