diff --git a/common/src/app/common/record.cljc b/common/src/app/common/record.cljc
index f4f564ef4..e8abbfc70 100644
--- a/common/src/app/common/record.cljc
+++ b/common/src/app/common/record.cljc
@@ -125,7 +125,9 @@
                       ~@(mapcat
                          (fn [f]
                            [(keyword f) `(set! (. ~this-sym ~(property-symbol f)) ~val-sym)])
-                         base-fields))
+                         base-fields)
+
+                      (set! (. ~this-sym ~'-$extmap) (cljs.core/assoc (. ~this-sym ~'-$extmap) ~key-sym ~val-sym)))
 
                     ~this-sym))
 
diff --git a/common/test/common_tests/record_test.cljc b/common/test/common_tests/record_test.cljc
new file mode 100644
index 000000000..809924cf4
--- /dev/null
+++ b/common/test/common_tests/record_test.cljc
@@ -0,0 +1,55 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+;;
+;; Copyright (c) KALEIDOS INC
+
+(ns common-tests.record-test
+  (:require
+   [app.common.data.macros :as dm]
+   [app.common.record :as cr]
+   [clojure.test :as t]))
+
+(cr/defrecord Sample [a b])
+
+(t/deftest operations
+  (let [o (pos->Sample 1 2)]
+
+    (t/testing "get"
+      (t/is (= 1 (:a o)))
+      (t/is (= 1 (get o :a)))
+      (t/is (= nil (get o :c)))
+      (t/is (= :foo (get o :c :foo))))
+
+    (t/testing "known assoc"
+      (let [o (assoc o :a 100)]
+        (t/is (= 100 (:a o)))))
+
+    (t/testing "unknown assoc"
+      (let [o (assoc o :c 176)]
+        (prn  o)
+        (t/is (= 1 (:a o)))
+        (t/is (= 2 (:b o)))
+        (t/is (= 176 (:c o)))))
+
+    (t/testing "contains"
+      (let [o (assoc o :c 176)]
+        (t/is (contains? o :a))
+        (t/is (contains? o :b))
+        (t/is (contains? o :c))
+        (t/is (not (contains? o :d)))))
+
+    #?(:cljs
+       (t/testing "transients"
+         (let [o (assoc o :c 123)
+               u (cr/clone o)]
+           (cr/assoc! u :a 10)
+           (cr/assoc! u :b 20)
+           (cr/assoc! u :c 124)
+
+           (t/is (= 10  (dm/get-prop u :a)))
+           (t/is (= 20  (dm/get-prop u :b)))
+           (t/is (= 124 (:c u)))
+           (t/is (not= u o)))))
+    ))
+