diff --git a/moses/FF/ConstrainedDecoding.h b/moses/FF/ConstrainedDecoding.h
index 97dfcb27c..6519c0a03 100644
--- a/moses/FF/ConstrainedDecoding.h
+++ b/moses/FF/ConstrainedDecoding.h
@@ -8,7 +8,6 @@
 
 namespace Moses
 {
-
 class ConstrainedDecodingState : public FFState
 {
 public:
@@ -29,6 +28,7 @@ protected:
 
 //////////////////////////////////////////////////////////////////
 
+// only allow hypotheses which match reference
 class ConstrainedDecoding : public StatefulFeatureFunction
 {
 public:
diff --git a/moses/FF/ControlRecombination.h b/moses/FF/ControlRecombination.h
index c1a59e75d..779eef7ab 100644
--- a/moses/FF/ControlRecombination.h
+++ b/moses/FF/ControlRecombination.h
@@ -29,6 +29,7 @@ protected:
 
 //////////////////////////////////////////////////////////////////
 
+// only allow recombination for the same output
 class ControlRecombination : public StatefulFeatureFunction
 {
 public: