Index: openacs-4/packages/categories/lib/tree-form.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/lib/tree-form.tcl,v
diff -u -N -r1.5 -r1.5.2.1
--- openacs-4/packages/categories/lib/tree-form.tcl	7 Aug 2017 23:48:05 -0000	1.5
+++ openacs-4/packages/categories/lib/tree-form.tcl	1 Mar 2019 10:49:28 -0000	1.5.2.1
@@ -7,7 +7,7 @@
 set languages [lang::system::get_locale_options]
 
 ad_form -name tree_form \
-    -mode [ad_decode [ad_form_new_p -key tree_id] 1 edit display] \
+    -mode [expr {[ad_form_new_p -key tree_id] ? "edit" : "display"}] \
     -action tree-form \
     -export { locale object_id ctx_id } \
     -form {