diff --git a/layout/generic/nsBlockFrame.cpp b/layout/generic/nsBlockFrame.cpp
index c9a7aecd5dc..b7d56a43ca2 100644
--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@@ -157,7 +157,7 @@ InitDebugFlags()
 #undef NOISY_REFLOW_REASON        // gives a little info about why each reflow was requested
 #undef REFLOW_STATUS_COVERAGE     // I think this is most useful for printing, to see which frames return "incomplete"
 #undef NOISY_SPACEMANAGER         // enables debug output for space manager use, useful for analysing reflow of floaters and positioned elements
-#define NOISY_BLOCK_INVALIDATE     // enables debug output for all calls to invalidate
+#undef NOISY_BLOCK_INVALIDATE     // enables debug output for all calls to invalidate
 #undef REALLY_NOISY_REFLOW       // some extra debug info
 
 #endif
diff --git a/layout/generic/nsBlockReflowState.cpp b/layout/generic/nsBlockReflowState.cpp
index c9a7aecd5dc..b7d56a43ca2 100644
--- a/layout/generic/nsBlockReflowState.cpp
+++ b/layout/generic/nsBlockReflowState.cpp
@@ -157,7 +157,7 @@ InitDebugFlags()
 #undef NOISY_REFLOW_REASON        // gives a little info about why each reflow was requested
 #undef REFLOW_STATUS_COVERAGE     // I think this is most useful for printing, to see which frames return "incomplete"
 #undef NOISY_SPACEMANAGER         // enables debug output for space manager use, useful for analysing reflow of floaters and positioned elements
-#define NOISY_BLOCK_INVALIDATE     // enables debug output for all calls to invalidate
+#undef NOISY_BLOCK_INVALIDATE     // enables debug output for all calls to invalidate
 #undef REALLY_NOISY_REFLOW       // some extra debug info
 
 #endif
diff --git a/layout/generic/nsBlockReflowState.h b/layout/generic/nsBlockReflowState.h
index c9a7aecd5dc..b7d56a43ca2 100644
--- a/layout/generic/nsBlockReflowState.h
+++ b/layout/generic/nsBlockReflowState.h
@@ -157,7 +157,7 @@ InitDebugFlags()
 #undef NOISY_REFLOW_REASON        // gives a little info about why each reflow was requested
 #undef REFLOW_STATUS_COVERAGE     // I think this is most useful for printing, to see which frames return "incomplete"
 #undef NOISY_SPACEMANAGER         // enables debug output for space manager use, useful for analysing reflow of floaters and positioned elements
-#define NOISY_BLOCK_INVALIDATE     // enables debug output for all calls to invalidate
+#undef NOISY_BLOCK_INVALIDATE     // enables debug output for all calls to invalidate
 #undef REALLY_NOISY_REFLOW       // some extra debug info
 
 #endif
diff --git a/layout/html/base/src/nsBlockFrame.cpp b/layout/html/base/src/nsBlockFrame.cpp
index c9a7aecd5dc..b7d56a43ca2 100644
--- a/layout/html/base/src/nsBlockFrame.cpp
+++ b/layout/html/base/src/nsBlockFrame.cpp
@@ -157,7 +157,7 @@ InitDebugFlags()
 #undef NOISY_REFLOW_REASON        // gives a little info about why each reflow was requested
 #undef REFLOW_STATUS_COVERAGE     // I think this is most useful for printing, to see which frames return "incomplete"
 #undef NOISY_SPACEMANAGER         // enables debug output for space manager use, useful for analysing reflow of floaters and positioned elements
-#define NOISY_BLOCK_INVALIDATE     // enables debug output for all calls to invalidate
+#undef NOISY_BLOCK_INVALIDATE     // enables debug output for all calls to invalidate
 #undef REALLY_NOISY_REFLOW       // some extra debug info
 
 #endif
diff --git a/layout/html/base/src/nsBlockReflowState.cpp b/layout/html/base/src/nsBlockReflowState.cpp
index c9a7aecd5dc..b7d56a43ca2 100644
--- a/layout/html/base/src/nsBlockReflowState.cpp
+++ b/layout/html/base/src/nsBlockReflowState.cpp
@@ -157,7 +157,7 @@ InitDebugFlags()
 #undef NOISY_REFLOW_REASON        // gives a little info about why each reflow was requested
 #undef REFLOW_STATUS_COVERAGE     // I think this is most useful for printing, to see which frames return "incomplete"
 #undef NOISY_SPACEMANAGER         // enables debug output for space manager use, useful for analysing reflow of floaters and positioned elements
-#define NOISY_BLOCK_INVALIDATE     // enables debug output for all calls to invalidate
+#undef NOISY_BLOCK_INVALIDATE     // enables debug output for all calls to invalidate
 #undef REALLY_NOISY_REFLOW       // some extra debug info
 
 #endif
diff --git a/layout/html/base/src/nsBlockReflowState.h b/layout/html/base/src/nsBlockReflowState.h
index c9a7aecd5dc..b7d56a43ca2 100644
--- a/layout/html/base/src/nsBlockReflowState.h
+++ b/layout/html/base/src/nsBlockReflowState.h
@@ -157,7 +157,7 @@ InitDebugFlags()
 #undef NOISY_REFLOW_REASON        // gives a little info about why each reflow was requested
 #undef REFLOW_STATUS_COVERAGE     // I think this is most useful for printing, to see which frames return "incomplete"
 #undef NOISY_SPACEMANAGER         // enables debug output for space manager use, useful for analysing reflow of floaters and positioned elements
-#define NOISY_BLOCK_INVALIDATE     // enables debug output for all calls to invalidate
+#undef NOISY_BLOCK_INVALIDATE     // enables debug output for all calls to invalidate
 #undef REALLY_NOISY_REFLOW       // some extra debug info
 
 #endif