Index: openacs-4/packages/acs-templating/tcl/list-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-templating/tcl/list-procs.tcl,v
diff -u -r1.72 -r1.73
--- openacs-4/packages/acs-templating/tcl/list-procs.tcl	27 Mar 2018 12:22:17 -0000	1.72
+++ openacs-4/packages/acs-templating/tcl/list-procs.tcl	6 Apr 2018 16:45:28 -0000	1.73
@@ -1098,7 +1098,7 @@
         lappend result "-decreasing"
     }
 
-    set result [concat $result $orderby_properties(multirow_cols)]
+    lappend result {*}$orderby_properties(multirow_cols)
 
     return $result
 }