css button styling

Is there a way to, for example, add the class btn-sm to the transcluded dropdown button? The default button is way too big in the bootstrap template i'm using.

Right now i've tackled it like this:

.user-menu-dropdown > button {
  padding: 9px 13px;
  font-size: 13px;
  line-height: 1.385;
  border-radius: 4px;
}

where the css rules are the styling for a bootstrap btn-sm and .user-menu-dropdown is added to the main ol list item as classname.

button size class is implementing but not has been released. If you look into the current master branch where the code at https://github.com/lordfriend/nya-bootstrap-select/blob/master/src/nya-bs-select.js#L82-L85 has already support the btn-sm, btn-lg, btn-xs. Notice that you cannot use button size class together with form-control class.