diff --git a/storage/folder.lisp b/storage/folder.lisp
index d2013d3..1ed624c 100644
--- a/storage/folder.lisp
+++ b/storage/folder.lisp
@@ -23,6 +23,7 @@
                  :short-name :fldr
                  :table-name :folders
                  :index-factory #'indexes
+                 :force-insert-when nil
                  :storage storage))
 
 (defun root (cont)
diff --git a/storage/tracking.lisp b/storage/tracking.lisp
index d9fda50..3435582 100644
--- a/storage/tracking.lisp
+++ b/storage/tracking.lisp
@@ -104,6 +104,7 @@
 
 (defun insert (track)
   (ensure-timestamp track)
+  (setf (trackid track) nil)
   (let* ((cont (container track))
          (st (storage cont))
          (table (storage:qualified-table-name st (table-name cont)))
@@ -122,7 +123,7 @@
     (storage:do-sql st
       (sxql:update table
         (apply #'sxql:make-clause ':set= (plist track))
-        (where (:= :trackid (trackid track)))))))
+        (sxql:where (list := :trackid (trackid track)))))))
 
 ;;;; auxiliary functions for queries, ...
 
diff --git a/test/test-storage.lisp b/test/test-storage.lisp
index 992cd7e..a3cb781 100644
--- a/test/test-storage.lisp
+++ b/test/test-storage.lisp
@@ -95,4 +95,6 @@
     (setf f1 (folder:create :child1 root))
     (== (tracking:trackid f1) 2)
     (== (shape:head-value f1 :parentid) "1")
+    (setf (shape:head-value f1 :ref) :dummy-0)
+    (tracking:save f1)
     ))
diff --git a/util.lisp b/util.lisp
index 7c6024e..de937bf 100644
--- a/util.lisp
+++ b/util.lisp
@@ -30,7 +30,7 @@
   `(loop for (,kvar ,vvar . nil) on ,plist by #'cddr ,@body))
 
 (defun filter-plist (pl keys)
-  (loop-plist pl k v when (find k keys) collect v))
+  (loop-plist pl k v when (find k keys) append (list k v)))
 
 (defun plist-pairs (pl)
   (loop-plist pl k v collect (list k v)))