Index: openacs-4/packages/acs-tcl/tcl/utilities-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-tcl/tcl/utilities-procs.tcl,v
diff -u -r1.189.2.134 -r1.189.2.135
--- openacs-4/packages/acs-tcl/tcl/utilities-procs.tcl	5 Sep 2022 15:57:38 -0000	1.189.2.134
+++ openacs-4/packages/acs-tcl/tcl/utilities-procs.tcl	5 Sep 2022 16:32:13 -0000	1.189.2.135
@@ -2218,63 +2218,15 @@
 
     @author Peter Marklund
 } {
-    if { [llength $list1] == 0 } {
-        # The empty list is always a subset of any list
-        return [list]
-    }
+    set missing [list]
 
-    set sorted_list1 [list]
-    foreach elm [lsort $list1] {
-        if { [llength $sorted_list1] == 0 || [lindex $sorted_list1 end] ne $elm } {
-            lappend sorted_list1 $elm
+    foreach e $list1 {
+        if {$e ni $list2 && $e ni $missing} {
+            lappend missing $e
         }
     }
-    set sorted_list2 [lsort $list2]
 
-    set len1 [llength $sorted_list1]
-    set len2 [llength $sorted_list2]
-
-    set missing_elms [list]
-
-    # Loop over list1 and list2 in sort order, comparing the elements
-
-    set index1 0
-    set index2 0
-    while { $index1 < $len1 && $index2 < $len2 } {
-        set elm1 [lindex $sorted_list1 $index1]
-        set elm2 [lindex $sorted_list2 $index2]
-        set compare [string compare $elm1 $elm2]
-
-        switch -exact -- $compare {
-            -1 {
-                # elm1 < elm2
-                # The first element in list1 is smaller than any element in list2,
-                # therefore this element cannot exist in list2, and therefore list1 is not a subset of list2
-                lappend missing_elms $elm1
-                incr index1
-            }
-            0 {
-                # A match, great, next element
-                incr index1
-                incr index2
-                continue
-            }
-            1 {
-                # elm1 > elm2
-                # Move to the next element in list2, knowing that this will be larger, and therefore
-                # potentially equal to the element in list1
-                incr index2
-            }
-        }
-    }
-
-    if { $index1 == $len1 } {
-        # We've reached the end of list1, finding all elements along the way, we're done
-        return $missing_elms
-    } else {
-        # One or more elements in list1 not found in list2
-        return [concat $missing_elms [lrange $sorted_list1 $index1 end]]
-    }
+    return $missing
 }
 
 ad_proc -public ad_tcl_list_list_to_ns_set {