diff --git a/zephyr/static/js/message_list.js b/zephyr/static/js/message_list.js
index c4c1adee02..cd437ed1ce 100644
--- a/zephyr/static/js/message_list.js
+++ b/zephyr/static/js/message_list.js
@@ -1,5 +1,6 @@
 /*jslint nomen: true */
-function MessageList(table_name) {
+function MessageList(table_name, opts) {
+    $.extend(this, {collapse_messages: true}, opts);
     this._items = [];
     this._hash = {};
     this.table_name = table_name;
@@ -147,7 +148,7 @@ MessageList.prototype = {
         });
     },
 
-    _render: function MessageList__render(messages, where, allow_collapse) {
+    _render: function MessageList__render(messages, where) {
         if (messages.length === 0)
             return;
 
@@ -162,7 +163,7 @@ MessageList.prototype = {
         var current_group = [];
         var new_message_groups = [];
 
-        if (where === 'top' && narrow.allow_collapse() && this._message_groups.length > 0) {
+        if (where === 'top' && this.collapse_messages && this._message_groups.length > 0) {
             // Delete the current top message group, and add it back in with these
             // messages, in order to collapse properly.
             //
@@ -188,7 +189,7 @@ MessageList.prototype = {
         $.each(messages, function (index, message) {
             message.include_recipient = false;
             message.include_bookend   = false;
-            if (util.same_recipient(prev, message) && allow_collapse) {
+            if (util.same_recipient(prev, message) && self.collapse_messages) {
                 current_group.push(message.id);
             } else {
                 if (current_group.length > 0)
@@ -293,19 +294,19 @@ MessageList.prototype = {
         }
     },
 
-    append: function MessageList_append(messages, allow_collapse) {
+    append: function MessageList_append(messages) {
         this._items = this._items.concat(messages);
         this._add_to_hash(messages);
         if (this.table_name) {
-            this._render(messages, 'bottom', allow_collapse);
+            this._render(messages, 'bottom');
         }
     },
 
-    prepend: function MessageList_prepend(messages, allow_collapse) {
+    prepend: function MessageList_prepend(messages) {
         this._items = messages.concat(this._items);
         this._add_to_hash(messages);
         if (this.table_name) {
-            this._render(messages, 'top', allow_collapse);
+            this._render(messages, 'top');
         }
     },
 
diff --git a/zephyr/static/js/narrow.js b/zephyr/static/js/narrow.js
index dd3c51de92..761ee59b73 100644
--- a/zephyr/static/js/narrow.js
+++ b/zephyr/static/js/narrow.js
@@ -37,12 +37,6 @@ exports.public_operators = function () {
     }
 };
 
-var allow_collapse;
-
-exports.allow_collapse = function () {
-    return (!filter_function) || allow_collapse;
-};
-
 /* Convert a list of operators to a string.
    Each operator is a key-value pair like
 
@@ -259,7 +253,6 @@ function build_filter(operators_mixed_case) {
 
 exports.activate = function (operators, opts) {
     opts = $.extend({}, {
-        allow_collapse: true,
         then_select_id: home_msg_list.selected_id()
     }, opts);
 
@@ -272,8 +265,6 @@ exports.activate = function (operators, opts) {
     filter_function   = build_filter(operators);
     current_operators = operators;
 
-    allow_collapse          = opts.allow_collapse;
-
     narrowed_msg_list = new MessageList('zfilt');
     current_msg_list = narrowed_msg_list;
 
diff --git a/zephyr/static/js/zephyr.js b/zephyr/static/js/zephyr.js
index a5ef806e87..bfede640a5 100644
--- a/zephyr/static/js/zephyr.js
+++ b/zephyr/static/js/zephyr.js
@@ -318,7 +318,7 @@ function add_message_metadata(message, dummy) {
     return message;
 }
 
-function add_messages_helper(messages, msg_list, predicate, allow_collapse) {
+function add_messages_helper(messages, msg_list, predicate) {
     var top_messages = [];
     var bottom_messages = [];
 
@@ -345,8 +345,8 @@ function add_messages_helper(messages, msg_list, predicate, allow_collapse) {
         });
     }
 
-    msg_list.prepend(top_messages, allow_collapse);
-    msg_list.append(bottom_messages, allow_collapse);
+    msg_list.prepend(top_messages);
+    msg_list.append(bottom_messages);
     return top_messages.length > 0;
 }
 
@@ -361,21 +361,18 @@ function add_messages(messages, msg_list, opts) {
     util.destroy_first_run_message();
     messages = $.map(messages, add_message_metadata);
 
-    var predicate, allow_collapse;
+    var predicate;
     if (msg_list === home_msg_list) {
         predicate = narrow.message_in_home;
-        allow_collapse = true;
     } else if (msg_list === narrowed_msg_list) {
         predicate = narrow.predicate();
-        allow_collapse = narrow.allow_collapse();
     } else if (msg_list === all_msg_list) {
         predicate = function () { return true; };
-        allow_collapse = true;
     } else {
         throw (new Error("Adding message to a list that is not known"));
     }
 
-    if (add_messages_helper(messages, msg_list, predicate, allow_collapse)) {
+    if (add_messages_helper(messages, msg_list, predicate)) {
         prepended = true;
     }