diff --git a/src/AudioIO.cpp b/src/AudioIO.cpp
index 7dcf76e92..0056e2704 100644
--- a/src/AudioIO.cpp
+++ b/src/AudioIO.cpp
@@ -456,6 +456,7 @@ TimeTrack and AudioIOListener and whether the playback is looped.
 #include "WaveTrack.h"
 #include "AutoRecovery.h"
 
+#include "effects/EffectManager.h"
 #include "prefs/QualityPrefs.h"
 #include "toolbars/ControlToolBar.h"
 #include "widgets/Meter.h"
diff --git a/src/Benchmark.cpp b/src/Benchmark.cpp
index 7a1ae3089..4cf834e93 100644
--- a/src/Benchmark.cpp
+++ b/src/Benchmark.cpp
@@ -34,6 +34,7 @@ of the BlockFile system.
 #include <wx/valtext.h>
 #include <wx/intl.h>
 
+#include "DirManager.h"
 #include "ShuttleGui.h"
 #include "Project.h"
 #include "WaveTrack.h"
diff --git a/src/CellularPanel.cpp b/src/CellularPanel.cpp
index 59e82cd2d..28248a966 100644
--- a/src/CellularPanel.cpp
+++ b/src/CellularPanel.cpp
@@ -31,6 +31,7 @@
 #include "CellularPanel.h"
 #include "Project.h"
 #include "UIHandle.h"
+#include "TrackPanelCell.h"
 #include "TrackPanelMouseEvent.h"
 #include "HitTestResult.h"
 #include "RefreshCode.h"
diff --git a/src/DirManager.cpp b/src/DirManager.cpp
index 6d5c5b724..1d381e9d3 100644
--- a/src/DirManager.cpp
+++ b/src/DirManager.cpp
@@ -106,6 +106,7 @@
 #include "widgets/Warning.h"
 #include "widgets/MultiDialog.h"
 #include "widgets/ErrorDialog.h"
+#include "widgets/ProgressDialog.h"
 
 #include "ondemand/ODManager.h"
 
diff --git a/src/Menus.cpp b/src/Menus.cpp
index 59689aa1f..66cccc4da 100644
--- a/src/Menus.cpp
+++ b/src/Menus.cpp
@@ -43,6 +43,7 @@
 #include "UndoManager.h"
 #include "WaveTrack.h"
 #include "commands/CommandManager.h"
+#include "effects/EffectManager.h"
 #include "prefs/TracksPrefs.h"
 #include "toolbars/ControlToolBar.h"
 #include "toolbars/ToolManager.h"
diff --git a/src/Project.cpp b/src/Project.cpp
index aa3921b36..b6f233dc5 100644
--- a/src/Project.cpp
+++ b/src/Project.cpp
@@ -127,6 +127,7 @@ scroll information.  It also has some status flags.
 #include "xml/XMLFileReader.h"
 #include "PlatformCompatibility.h"
 #include "Experimental.h"
+#include "effects/EffectManager.h"
 #include "export/Export.h"
 #include "FileNames.h"
 #include "BlockFile.h"
diff --git a/src/Project.h b/src/Project.h
index b6099d8f5..afec62264 100644
--- a/src/Project.h
+++ b/src/Project.h
@@ -21,14 +21,11 @@
 #include "Audacity.h"
 #include "Experimental.h"
 
-#include "widgets/OverlayPanel.h"
-
-#include "DirManager.h"
+#include "Track.h"
 #include "SelectionState.h"
 #include "ViewInfo.h"
 #include "TrackPanelListener.h"
 #include "AudioIOListener.h"
-#include "effects/EffectManager.h"
 #include "xml/XMLTagHandler.h"
 #include "toolbars/SelectionBarListener.h"
 #include "toolbars/SpectralSelectionBarListener.h"
@@ -59,6 +56,7 @@ class AudacityProject;
 class AutoSaveFile;
 class Importer;
 class ODLock;
+class Overlay;
 class RecordingRecoveryHandler;
 class TrackList;
 class Tags;
@@ -116,6 +114,8 @@ bool IsWindowAccessible(wxRect *requestedRect);
 using AProjectHolder = std::shared_ptr< AudacityProject >;
 using AProjectArray = std::vector< AProjectHolder >;
 
+using WaveTrackArray = std::vector < std::shared_ptr < WaveTrack > >;
+
 extern AProjectArray gAudacityProjects;
 
 
diff --git a/src/TimerRecordDialog.cpp b/src/TimerRecordDialog.cpp
index f824f91f5..c55d37e40 100644
--- a/src/TimerRecordDialog.cpp
+++ b/src/TimerRecordDialog.cpp
@@ -33,6 +33,7 @@
 #include <wx/timer.h>
 #include <wx/dynlib.h> //<! For windows.h
 
+#include "DirManager.h"
 #include "ShuttleGui.h"
 #include "Menus.h"
 #include "Project.h"
diff --git a/src/effects/Contrast.cpp b/src/effects/Contrast.cpp
index f5ab214b3..a0144e844 100644
--- a/src/effects/Contrast.cpp
+++ b/src/effects/Contrast.cpp
@@ -30,6 +30,7 @@
 #define finite(x) _finite(x)
 #endif
 
+#include <wx/button.h>
 #include <wx/filedlg.h>
 #include <wx/valtext.h>
 #include <wx/log.h>
diff --git a/src/effects/Effect.cpp b/src/effects/Effect.cpp
index 46b1c7667..edfeb4971 100644
--- a/src/effects/Effect.cpp
+++ b/src/effects/Effect.cpp
@@ -38,11 +38,13 @@ greater use in future.
 
 #include "audacity/ConfigInterface.h"
 
+#include "EffectManager.h"
 #include "../AudacityException.h"
 #include "../AudioIO.h"
 #include "../LabelTrack.h"
 #include "../Menus.h"
 #include "../Mix.h"
+#include "../PluginManager.h"
 #include "../Prefs.h"
 #include "../Project.h"
 #include "../ShuttleGui.h"
diff --git a/src/effects/ToneGen.cpp b/src/effects/ToneGen.cpp
index 51b4c489c..04f687555 100644
--- a/src/effects/ToneGen.cpp
+++ b/src/effects/ToneGen.cpp
@@ -24,6 +24,7 @@ frequency changes smoothly during the tone.
 #include <math.h>
 #include <float.h>
 
+#include <wx/choice.h>
 #include <wx/intl.h>
 #include <wx/valgen.h>
 
diff --git a/src/effects/nyquist/Nyquist.cpp b/src/effects/nyquist/Nyquist.cpp
index 0fad62773..d0666246e 100644
--- a/src/effects/nyquist/Nyquist.cpp
+++ b/src/effects/nyquist/Nyquist.cpp
@@ -44,7 +44,9 @@ effects from this one class.
 #include <wx/numformatter.h>
 #include <wx/stdpaths.h>
 
+#include "../EffectManager.h"
 #include "../../AudacityApp.h"
+#include "../../DirManager.h"
 #include "../../FileException.h"
 #include "../../FileNames.h"
 #include "../../Internat.h"
diff --git a/src/effects/vamp/VampEffect.cpp b/src/effects/vamp/VampEffect.cpp
index 845508820..881da17d6 100644
--- a/src/effects/vamp/VampEffect.cpp
+++ b/src/effects/vamp/VampEffect.cpp
@@ -24,6 +24,7 @@
 #include <wx/wxprec.h>
 #include <wx/button.h>
 #include <wx/checkbox.h>
+#include <wx/choice.h>
 #include <wx/combobox.h>
 #include <wx/sizer.h>
 #include <wx/slider.h>
diff --git a/src/export/ExportMultiple.cpp b/src/export/ExportMultiple.cpp
index 6654daeca..13cefe44e 100644
--- a/src/export/ExportMultiple.cpp
+++ b/src/export/ExportMultiple.cpp
@@ -38,6 +38,7 @@
 
 #include "Export.h"
 
+#include "../DirManager.h"
 #include "../Internat.h"
 #include "../FileFormats.h"
 #include "../FileNames.h"
diff --git a/src/menus/PluginMenus.cpp b/src/menus/PluginMenus.cpp
index 5784cc7cc..6b0654bf1 100644
--- a/src/menus/PluginMenus.cpp
+++ b/src/menus/PluginMenus.cpp
@@ -15,6 +15,7 @@
 #include "../commands/CommandManager.h"
 #include "../commands/ScreenshotCommand.h"
 #include "../effects/Contrast.h"
+#include "../effects/EffectManager.h"
 
 // private helper classes and functions
 namespace {
diff --git a/src/menus/TrackMenus.cpp b/src/menus/TrackMenus.cpp
index fec31fdb8..7d7592fb6 100644
--- a/src/menus/TrackMenus.cpp
+++ b/src/menus/TrackMenus.cpp
@@ -13,6 +13,7 @@
 #include "../WaveTrack.h"
 #include "../commands/CommandContext.h"
 #include "../commands/CommandManager.h"
+#include "../effects/EffectManager.h"
 #include "../widgets/ASlider.h"
 
 #include <wx/combobox.h>
diff --git a/src/prefs/SpectrumPrefs.cpp b/src/prefs/SpectrumPrefs.cpp
index 0a43bcbaa..074830c90 100644
--- a/src/prefs/SpectrumPrefs.cpp
+++ b/src/prefs/SpectrumPrefs.cpp
@@ -17,6 +17,7 @@
 #include "../Audacity.h"
 #include "SpectrumPrefs.h"
 
+#include <wx/choice.h>
 #include <wx/defs.h>
 #include <wx/intl.h>
 #include <wx/checkbox.h>
diff --git a/src/prefs/WaveformPrefs.cpp b/src/prefs/WaveformPrefs.cpp
index ddd132770..39b8c1925 100644
--- a/src/prefs/WaveformPrefs.cpp
+++ b/src/prefs/WaveformPrefs.cpp
@@ -19,6 +19,7 @@ Paul Licameli
 #include "GUISettings.h"
 
 #include <wx/checkbox.h>
+#include <wx/choice.h>
 
 #include "../Project.h"
 
diff --git a/src/tracks/playabletrack/wavetrack/ui/WaveTrackControls.cpp b/src/tracks/playabletrack/wavetrack/ui/WaveTrackControls.cpp
index 6a562fdd1..262ee840e 100644
--- a/src/tracks/playabletrack/wavetrack/ui/WaveTrackControls.cpp
+++ b/src/tracks/playabletrack/wavetrack/ui/WaveTrackControls.cpp
@@ -24,6 +24,7 @@ Paul Licameli split from TrackPanel.cpp
 #include "../../../../TrackPanel.h"
 #include "../../../../TrackPanelMouseEvent.h"
 #include "../../../../widgets/PopupMenuTable.h"
+#include "../../../../effects/EffectManager.h"
 #include "../../../../ondemand/ODManager.h"
 #include "../../../../prefs/PrefsDialog.h"
 #include "../../../../prefs/SpectrumPrefs.h"
diff --git a/src/tracks/ui/BackgroundCell.cpp b/src/tracks/ui/BackgroundCell.cpp
index da619be30..23067d455 100644
--- a/src/tracks/ui/BackgroundCell.cpp
+++ b/src/tracks/ui/BackgroundCell.cpp
@@ -14,6 +14,7 @@ Paul Licameli split from TrackPanel.cpp
 #include "../../HitTestResult.h"
 #include "../../Project.h"
 #include "../../RefreshCode.h"
+#include "../../Track.h"
 #include "../../TrackPanelMouseEvent.h"
 #include "../../UIHandle.h"
 
diff --git a/src/tracks/ui/SliderHandle.cpp b/src/tracks/ui/SliderHandle.cpp
index 86f2ce4ad..abfd73f9d 100644
--- a/src/tracks/ui/SliderHandle.cpp
+++ b/src/tracks/ui/SliderHandle.cpp
@@ -14,6 +14,7 @@ Paul Licameli
 #include "../../HitTestResult.h"
 #include "../../Project.h"
 #include "../../RefreshCode.h"
+#include "../../Track.h"
 #include "../../TrackPanelMouseEvent.h"
 
 SliderHandle::SliderHandle