update

resources/views/admin/orders/artboard.blade.php

@@ -19,6 +19,8 @@
                             <select class="form-control mr-1" name="building_id"
                                     onchange="$(this).closest('form').submit()">
                                 @foreach($buildings as $pp)
+                                    <option
+                                        value="" @if('' == $building_id) {{ "selected" }}@endif>{{$pp->name}}</option>
                                     <option
                                         value="{{$pp->id}}" @if($pp->id == $building_id) {{ "selected" }}@endif>{{$pp->name}}</option>
                                 @endforeach