diff --git a/lib/resource/abstract/ClauseI.gf b/lib/resource/abstract/ClauseI.gf
index 8fb69397d..fb8fb3b3e 100644
--- a/lib/resource/abstract/ClauseI.gf
+++ b/lib/resource/abstract/ClauseI.gf
@@ -2,7 +2,7 @@
 
 incomplete concrete ClauseI of Clause = open Rules, Verbphrase in {
 
-  flags optimize=all ;
+  flags optimize=all_subs ;
 
   lin
 
diff --git a/lib/resource/english/ClauseEng.gf b/lib/resource/english/ClauseEng.gf
index d7b7b545f..be6bbb6db 100644
--- a/lib/resource/english/ClauseEng.gf
+++ b/lib/resource/english/ClauseEng.gf
@@ -6,7 +6,7 @@ concrete ClauseEng of Clause = CategoriesEng **
 
   open Prelude, SyntaxEng in {
 
-  flags optimize=all ;
+  flags optimize=all_subs ;
 
   lin
   SPredV np v = predVerbClause np v (complVerb v) ;
diff --git a/lib/resource/english/RulesEng.gf b/lib/resource/english/RulesEng.gf
index f162763ab..221af7bdb 100644
--- a/lib/resource/english/RulesEng.gf
+++ b/lib/resource/english/RulesEng.gf
@@ -22,7 +22,7 @@
 concrete RulesEng of Rules = CategoriesEng ** open Prelude, SyntaxEng in {
 
 flags 
-  optimize=all ;
+  optimize=all_subs ;
 
 lin 
   UseN  = noun2CommNounPhrase ;
diff --git a/lib/resource/scandinavian/RulesScand.gf b/lib/resource/scandinavian/RulesScand.gf
index fba633553..690857eaa 100644
--- a/lib/resource/scandinavian/RulesScand.gf
+++ b/lib/resource/scandinavian/RulesScand.gf
@@ -3,7 +3,7 @@
 incomplete concrete RulesScand of Rules = CategoriesScand ** 
   open Prelude, SyntaxScand in {
 
-flags optimize=all ;
+flags optimize=all_subs ;
 
 lin 
   UseN = noun2CommNounPhrase ;