Index: openacs-4/packages/xowiki/tcl/lcs-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowiki/tcl/lcs-procs.tcl,v
diff -u -r1.6 -r1.7
--- openacs-4/packages/xowiki/tcl/lcs-procs.tcl	25 Apr 2018 19:47:48 -0000	1.6
+++ openacs-4/packages/xowiki/tcl/lcs-procs.tcl	9 May 2018 15:33:34 -0000	1.7
@@ -35,8 +35,8 @@
 
 proc list::longestCommonSubsequence { sequence1 sequence2 } {
 
-  set seta {}
-  set setb {}
+  set seta [list]
+  set setb [list]
 
   # Construct a set of equivalence classes of lines in file 2