diff --git a/include/audacity/EffectInterface.h b/include/audacity/EffectInterface.h
index 4a681a7af..1352a7981 100755
--- a/include/audacity/EffectInterface.h
+++ b/include/audacity/EffectInterface.h
@@ -47,8 +47,6 @@
 #include "audacity/ConfigInterface.h"
 #include "audacity/EffectAutomationParameters.h" // for command automation
 
-#include <wx/dialog.h>
-
 typedef enum EffectType : int
 {
    EffectTypeNone,
@@ -99,6 +97,7 @@ public:
    virtual bool SupportsAutomation() = 0;
 };
 
+class wxDialog;
 class EffectUIHostInterface;
 class EffectUIClientInterface;
 
diff --git a/src/FreqWindow.h b/src/FreqWindow.h
index 54d73cead..bfa34d176 100644
--- a/src/FreqWindow.h
+++ b/src/FreqWindow.h
@@ -14,7 +14,6 @@
 #include "MemoryX.h"
 #include <vector>
 #include <wx/panel.h>
-#include <wx/dialog.h>
 #include <wx/font.h> // member variable
 #include <wx/statusbr.h> // to inherit
 #include "SampleFormat.h"
diff --git a/src/SplashDialog.h b/src/SplashDialog.h
index 3cbb7201e..6c134343a 100644
--- a/src/SplashDialog.h
+++ b/src/SplashDialog.h
@@ -12,7 +12,6 @@
 #define __AUDACITY_SPLASH_DLG__
 
 #include "MemoryX.h"
-#include <wx/dialog.h>
 #include "widgets/wxPanelWrapper.h"
 
 class wxBitmap;
diff --git a/src/TimerRecordDialog.h b/src/TimerRecordDialog.h
index 0c800f18c..edf54e71a 100644
--- a/src/TimerRecordDialog.h
+++ b/src/TimerRecordDialog.h
@@ -16,7 +16,6 @@
 #ifndef __AUDACITY_TIMERRECORD_DIALOG__
 #define __AUDACITY_TIMERRECORD_DIALOG__
 
-#include <wx/dialog.h>
 #include <wx/textctrl.h> // to inherit
 #include <wx/datectrl.h>
 #include <wx/calctrl.h>
diff --git a/src/effects/EffectManager.h b/src/effects/EffectManager.h
index 955c90bed..77842dbc5 100644
--- a/src/effects/EffectManager.h
+++ b/src/effects/EffectManager.h
@@ -15,7 +15,6 @@
 #include "../Experimental.h"
 
 #include <vector>
-#include <wx/dialog.h>
 #include <wx/listbox.h>
 
 #include "audacity/EffectInterface.h"
diff --git a/src/effects/Equalization.h b/src/effects/Equalization.h
index b6bfb6bba..b0284fbd5 100644
--- a/src/effects/Equalization.h
+++ b/src/effects/Equalization.h
@@ -19,7 +19,6 @@
 
 #include <wx/setup.h> // for wxUSE_* macros
 #include <wx/panel.h>
-#include <wx/dialog.h>
 #include <wx/radiobut.h>
 
 #if wxUSE_ACCESSIBILITY
diff --git a/src/effects/NoiseRemoval.h b/src/effects/NoiseRemoval.h
index 3d5708145..a6dee084e 100644
--- a/src/effects/NoiseRemoval.h
+++ b/src/effects/NoiseRemoval.h
@@ -22,7 +22,6 @@
 
 #include "../MemoryX.h"
 #include "../SampleFormat.h"
-#include <wx/dialog.h>
 
 class wxButton;
 class wxSizer;
diff --git a/src/effects/ScoreAlignDialog.h b/src/effects/ScoreAlignDialog.h
index 2d8469c95..b00d22ef6 100644
--- a/src/effects/ScoreAlignDialog.h
+++ b/src/effects/ScoreAlignDialog.h
@@ -13,8 +13,6 @@
 
 #ifdef EXPERIMENTAL_SCOREALIGN
 
-#include <wx/dialog.h>
-
 #if 1
 
 #include "ScoreAlignParams.h"
diff --git a/src/effects/audiounits/AudioUnitEffect.h b/src/effects/audiounits/AudioUnitEffect.h
index 0aee4a91d..c42db3522 100644
--- a/src/effects/audiounits/AudioUnitEffect.h
+++ b/src/effects/audiounits/AudioUnitEffect.h
@@ -16,7 +16,6 @@
 
 #include "../../MemoryX.h"
 #include <vector>
-#include <wx/dialog.h>
 
 #include <AudioToolbox/AudioUnitUtilities.h>
 #include <AudioUnit/AudioUnit.h>
diff --git a/src/effects/ladspa/LadspaEffect.h b/src/effects/ladspa/LadspaEffect.h
index 9643c0d09..89198b41b 100644
--- a/src/effects/ladspa/LadspaEffect.h
+++ b/src/effects/ladspa/LadspaEffect.h
@@ -14,7 +14,6 @@ class wxTextCtrl;
 class wxCheckBox;
 
 #include "../../MemoryX.h"
-#include <wx/dialog.h>
 #include <wx/dynlib.h> // member variable
 
 #include "audacity/EffectInterface.h"
diff --git a/src/effects/lv2/LV2Effect.h b/src/effects/lv2/LV2Effect.h
index 09e5d2c78..2b1dabfb2 100644
--- a/src/effects/lv2/LV2Effect.h
+++ b/src/effects/lv2/LV2Effect.h
@@ -17,7 +17,6 @@ class wxArrayString;
 
 #include "../../MemoryX.h"
 #include <vector>
-#include <wx/dialog.h>
 
 #include "lv2/lv2plug.in/ns/ext/atom/forge.h"
 #include "lv2/lv2plug.in/ns/ext/data-access/data-access.h"
diff --git a/src/effects/nyquist/Nyquist.h b/src/effects/nyquist/Nyquist.h
index cef16a667..91c30eeaf 100644
--- a/src/effects/nyquist/Nyquist.h
+++ b/src/effects/nyquist/Nyquist.h
@@ -12,7 +12,6 @@
 #define __AUDACITY_EFFECT_NYQUIST__
 
 #include <wx/datetime.h>
-#include <wx/dialog.h>
 #include <wx/textbuf.h>
 
 #include "../Effect.h"
diff --git a/src/export/Export.h b/src/export/Export.h
index 1a735e7b7..aea8901c7 100644
--- a/src/export/Export.h
+++ b/src/export/Export.h
@@ -13,7 +13,6 @@
 
 #include "../MemoryX.h"
 #include <vector>
-#include <wx/dialog.h>
 #include "../Tags.h"
 #include "../SampleFormat.h"
 #include "../widgets/wxPanelWrapper.h"
diff --git a/src/export/ExportMultiple.h b/src/export/ExportMultiple.h
index 2b5fba317..b257b99bf 100644
--- a/src/export/ExportMultiple.h
+++ b/src/export/ExportMultiple.h
@@ -11,8 +11,6 @@
 #ifndef __AUDACITY_EXPORT_MULTIPLE__
 #define __AUDACITY_EXPORT_MULTIPLE__
 
-#include <wx/dialog.h>
-
 #include "Export.h"
 #include "../Tags.h"       // we need to know about the Tags class for metadata
 #include "../wxFileNameWrapper.h" // member variable below
diff --git a/src/prefs/PrefsDialog.h b/src/prefs/PrefsDialog.h
index 17936efd0..db7559fab 100644
--- a/src/prefs/PrefsDialog.h
+++ b/src/prefs/PrefsDialog.h
@@ -13,7 +13,6 @@
 #define __AUDACITY_PREFS_DIALOG__
 
 #include <vector>
-#include <wx/dialog.h>
 #include <wx/treebook.h>
 #include "../widgets/wxPanelWrapper.h"
 #include "../Internat.h"
diff --git a/src/widgets/ExpandingToolBar.h b/src/widgets/ExpandingToolBar.h
index 12e516f61..9bb8f3071 100644
--- a/src/widgets/ExpandingToolBar.h
+++ b/src/widgets/ExpandingToolBar.h
@@ -14,7 +14,6 @@
 #include "../MemoryX.h"
 #include <vector>
 #include <wx/defs.h>
-#include <wx/dialog.h>
 #include <wx/dragimag.h> // use macros and typedefs in this header
 #include <wx/panel.h>
 #include <wx/timer.h>
diff --git a/src/widgets/wxPanelWrapper.h b/src/widgets/wxPanelWrapper.h
index e34923aef..0bc97ca57 100644
--- a/src/widgets/wxPanelWrapper.h
+++ b/src/widgets/wxPanelWrapper.h
@@ -11,7 +11,7 @@
 
 #include "../MemoryX.h"
 #include <wx/panel.h>
-#include <wx/dialog.h>
+#include <wx/dialog.h> // to inherit
 
 #include "../Internat.h"