Select dropdown not displaying properly in the cshtml View - asp.net-mvc

Question

The dropdown on the image below do not display properly. I want the dropdown to cover the length of the Modal Popup. The Button on the page fire properly I have no issue with my Controller. Any help to resolve this issue will be appreciated
View Code
<a class="btn w-xs btn-primary" data-toggle="modal" data-target=".bootstrapmodal"><i class="fa fa-book" aria-hidden="true"></i><span id="#ViewBag.Group"> Add New Member</span></a>
<div class="modal fade bootstrapmodal ">
<div class="modal-dialog modal-lg">
<div class="modal-content">
<div class="modal-header">
<button data-dismiss="modal" class="close"><span>×</span></button>
<div class=" modal-title"><h3>Add User to Active Directory Group #ViewBag.Group </h3></div>
</div>
<div class="modal-body">
<div class="content">
#using (Html.BeginForm("AddNewUser", "ActiveDirectoryMember", FormMethod.Post, new { enctype = "multipart/form-data", id = "addUser" }))
{
#Html.ValidationSummary(true, "", new { #class = "text-danger" })
#Html.AntiForgeryToken()
<div class="panel ">
<div class="panel-body ">
<div class="form-horizontal">
<input type="hidden" name="groupName" value="#ViewBag.Group" />
<div class="form-group">
#Html.Label("Technician", new { #class = "control-label col-md-2 required" })
<div class="input-group">
<div class="col-md-8">
<select id="userId" name="userId" class="form-control s2-search-box2">
<option value="">Click search for a staff member</option>
</select>
</div>
</div>
</div>
<div class="form-group">
<div class="col-md-2">
</div>
<div class="col-md-2">
<button type="submit" class="btn btn-success" id="addUser">
<i class="fa fa-plus-circle"></i>
Add New User
</button>
</div>
</div>
</div>
</div>
</div>
}
</div>
</div>
<div class="modal-footer">
<button class="btn btn-default" data-dismiss="modal">
<i class="fa fa-ban"></i>
Cancel
</button>
</div>
</div>
</div>
</div>