diff --git a/frontend_tests/node_tests/message_store.js b/frontend_tests/node_tests/message_store.js
index 43fc237fd3..3846267d80 100644
--- a/frontend_tests/node_tests/message_store.js
+++ b/frontend_tests/node_tests/message_store.js
@@ -203,6 +203,7 @@ run_test('message_id_change', () => {
 
     set_global('pointer', {
         furthest_read: 401,
+        set_furthest_read: function (value) { this.furthest_read = value; },
     });
 
     set_global('message_list', {});
diff --git a/frontend_tests/node_tests/server_events.js b/frontend_tests/node_tests/server_events.js
index f635ae994e..9e241bf6e6 100644
--- a/frontend_tests/node_tests/server_events.js
+++ b/frontend_tests/node_tests/server_events.js
@@ -67,6 +67,9 @@ run_test('pointer_event', () => {
     };
 
     global.pointer.furthest_read = 0;
+    global.pointer.set_furthest_read = function (value) {
+        this.furthest_read = value;
+    };
     global.pointer.server_furthest_read = 0;
     server_events._get_events_success([event]);
     assert.equal(global.pointer.furthest_read, event.pointer);
diff --git a/static/js/message_store.js b/static/js/message_store.js
index 426e9082d6..ed3300cec7 100644
--- a/static/js/message_store.js
+++ b/static/js/message_store.js
@@ -176,7 +176,7 @@ exports.reify_message_id = function (opts) {
     var old_id = opts.old_id;
     var new_id = opts.new_id;
     if (pointer.furthest_read === old_id) {
-        pointer.furthest_read = new_id;
+        pointer.set_furthest_read(new_id);
     }
     if (stored_messages[old_id]) {
         stored_messages[new_id] = stored_messages[old_id];
diff --git a/static/js/pointer.js b/static/js/pointer.js
index 050a281172..dd354dad75 100644
--- a/static/js/pointer.js
+++ b/static/js/pointer.js
@@ -11,6 +11,9 @@ exports.recenter_pointer_on_display = false;
 // when All Messages is next clicked by the user
 exports.suppress_scroll_pointer_update = false;
 exports.furthest_read = -1;
+exports.set_furthest_read = function (value) {
+    exports.furthest_read = value;
+};
 exports.server_furthest_read = -1;
 
 var pointer_update_in_flight = false;
diff --git a/static/js/server_events.js b/static/js/server_events.js
index 7ead05dc4e..0b00b72797 100644
--- a/static/js/server_events.js
+++ b/static/js/server_events.js
@@ -133,7 +133,7 @@ function get_events_success(events) {
 
     if (new_pointer !== undefined
         && new_pointer > pointer.furthest_read) {
-        pointer.furthest_read = new_pointer;
+        pointer.set_furthest_read(new_pointer);
         pointer.server_furthest_read = new_pointer;
         home_msg_list.select_id(new_pointer, {then_scroll: true, use_closest: true});
     }