Web.Admin/Modals/Participant/_shirtsize.html
<label for="name" class="col-sm-3 control-label">Shirt</label>
<div class="col-sm-9">
<select id="shirtSize" data-ng-model="model.participant.ShirtSize">
<!--<optgroup label="Ladies">
<option value="L-S">Ladies Small</option>
<option value="L-M">Ladies Medium</option>
<option value="L-L">Ladies Large</option>
<option value="L-XL">Ladies X-Large</option>
</optgroup>-->
<optgroup label="Mens">
<option value="M-S">Small</option>
<option value="M-M">Medium</option>
<option value="M-L">Large</option>
<option value="M-XL">X-Large</option>
</optgroup>
</select>
</div>