Bugfix. Still render server input field, just make it hidden.

src/templates/room_panel.html

@@ -4,8 +4,8 @@
         <input type="text" name="chatroom" class="new-chatroom-name" placeholder="{{label_room_name}}"/>
         {[ if (server_input_type != 'hidden') { ]}
             <label{{server_label_global_attr}}>{{label_server}}</label>
-            <input type="{{server_input_type}}" name="server" class="new-chatroom-server" placeholder="{{label_server}}"/>
         {[ } ]}
+        <input type="{{server_input_type}}" name="server" class="new-chatroom-server" placeholder="{{label_server}}"/>
         <input type="submit" class="pure-button button-primary" name="join" value="{{label_join}}"/>
         <input type="button" class="pure-button button-secondary" name="show" id="show-rooms" value="{{label_show_rooms}}"/>
     </fieldset>