diff --git a/src/AllThemeResources.h b/src/AllThemeResources.h
index 617d8e439..8acbd7c37 100644
--- a/src/AllThemeResources.h
+++ b/src/AllThemeResources.h
@@ -44,6 +44,7 @@ from there.  Audacity will look for a file called "Pause.png".
 // Note: No '#ifndef/#define' pair on this header file.
 // we want to include it multiple times in Theme.cpp.
 
+#include "Experimental.h"
 #include "MacroMagic.h"
 #define XPMS_RETIRED
 
diff --git a/src/commands/CommandManager.h b/src/commands/CommandManager.h
index 0671bad88..76ef9cc33 100644
--- a/src/commands/CommandManager.h
+++ b/src/commands/CommandManager.h
@@ -12,6 +12,8 @@
 #ifndef __AUDACITY_COMMAND_MANAGER__
 #define __AUDACITY_COMMAND_MANAGER__
 
+#include "../Experimental.h"
+
 #include <wx/string.h>
 #include <wx/dynarray.h>
 #include <wx/menu.h>
diff --git a/src/effects/EffectManager.h b/src/effects/EffectManager.h
index 5852d674c..bd4eae198 100644
--- a/src/effects/EffectManager.h
+++ b/src/effects/EffectManager.h
@@ -21,6 +21,8 @@ effects.
 #ifndef __AUDACITY_EFFECTMANAGER__
 #define __AUDACITY_EFFECTMANAGER__
 
+#include "../Experimental.h"
+
 #include <wx/choice.h>
 #include <wx/dialog.h>
 #include <wx/event.h>
diff --git a/src/effects/Equalization.h b/src/effects/Equalization.h
index 5cc977bfa..9414b6744 100644
--- a/src/effects/Equalization.h
+++ b/src/effects/Equalization.h
@@ -15,6 +15,8 @@
 #define NUM_PTS 180
 #define PANELBORDER 1   // only increase from '1' for testing purposes - MJS
 
+#include "../Experimental.h"
+
 #include <wx/button.h>
 #include <wx/panel.h>
 #include <wx/dialog.h>