Index: library/nx/nx.tcl
===================================================================
diff -u -N -rb8ca306282c9a1000b1c93ffd97f7f4673953f65 -r9df6b50237ae89bc387ec217237538d08c0f8d39
--- library/nx/nx.tcl	(.../nx.tcl)	(revision b8ca306282c9a1000b1c93ffd97f7f4673953f65)
+++ library/nx/nx.tcl	(.../nx.tcl)	(revision 9df6b50237ae89bc387ec217237538d08c0f8d39)
@@ -1847,7 +1847,8 @@
     }
 
     set restore [:removeTraces $object *]
-    ::nsf::var::set $object ${:name} ${:default}
+    # was: ::nsf::var::set $object ${:name} ${:default}
+    ::nsf::var::set $object ${:name} $value
     if {[info exists restore]} { {*}$restore }
   }
 
@@ -2238,6 +2239,11 @@
     if {![info exists trace] && [info exists :trace] && ${:trace} ne "none"} {
       set trace ${:trace}
     }
+
+    if {$parameterOptions ne "" && "substdefault" in [split $parameterOptions ,]} {
+      set defaultValue [subst $defaultValue]
+    }
+
     if {$initblock eq "" && !$configurable && !$incremental
         && $accessor eq "none" && ![info exists trace]} {
       #
@@ -2257,7 +2263,7 @@
 	  # we rely here that the nsf::is error message expresses the implementation limits
 	  set noptions {}
 	  foreach o [split $parameterOptions ,] {
-	    if {$o ne "noconfig"} {lappend noptions $o}
+	    if {$o ni {noconfig substdefault}} {lappend noptions $o}
 	  }
 
 	  set parameterOptions [join $noptions ,]