Bugfix. The chatroom was being joined twice, causing duplication.

converse.js

@@ -1900,9 +1900,6 @@
                     'chatroom': true,
                     'box_id' : b64_sha1(jid)
                 });
-                if (!chatroom.get('connected')) {
-                    converse.chatboxviews.get(jid).connect(null);
-                }
             }
         });
 

src/templates/chatroom_password_form.html

+<div class="chatroom-form-container">
+    <form class="chatroom-form">
+        <legend>{{heading}}</legend>
+        <label>{{label_password}}<input type="password" name="password"/></label>
+        <input type="submit" value="{{label_submit}}"/>
+    </form>
+</div>