diff --git a/src/AudacityApp.cpp b/src/AudacityApp.cpp
index 29c98ae3d..b4581a024 100644
--- a/src/AudacityApp.cpp
+++ b/src/AudacityApp.cpp
@@ -75,7 +75,6 @@ It handles initialization and termination by subclassing wxApp.
 #include "DirManager.h"
 #include "commands/CommandHandler.h"
 #include "commands/AppCommandEvent.h"
-#include "effects/Contrast.h"
 #include "widgets/ASlider.h"
 #include "FFmpeg.h"
 #include "LangChoice.h"
diff --git a/src/AudacityHeaders.h b/src/AudacityHeaders.h
index 74d9d846f..dc75e0c17 100644
--- a/src/AudacityHeaders.h
+++ b/src/AudacityHeaders.h
@@ -51,7 +51,6 @@
 #include "Envelope.h"
 #include "FFT.h"
 #include "FileFormats.h"
-#include "FreqWindow.h"
 #include "ImageManipulation.h"
 #include "LabelTrack.h"
 #include "Mix.h"
diff --git a/src/Project.cpp b/src/Project.cpp
index 42c9bdd55..60c3af571 100644
--- a/src/Project.cpp
+++ b/src/Project.cpp
@@ -98,22 +98,17 @@ scroll information.  It also has some status flags.
 #include "AdornedRulerPanel.h"
 #include "Clipboard.h"
 #include "widgets/FileHistory.h"
-#include "FreqWindow.h"
-#include "effects/Contrast.h"
 #include "AutoRecovery.h"
 #include "AColor.h"
 #include "AudioIO.h"
-#include "BatchProcessDialog.h"
 #include "Dependencies.h"
 #include "Diags.h"
-#include "HistoryWindow.h"
+#include "export/Export.h"
 #include "InconsistencyException.h"
-#include "MixerBoard.h"
 #include "import/Import.h"
 #include "KeyboardCapture.h"
 #include "LabelTrack.h"
 #include "Legacy.h"
-#include "LyricsWindow.h"
 #include "Menus.h"
 #include "MissingAliasFileDialog.h"
 #include "Mix.h"
@@ -1352,6 +1347,8 @@ AudacityProject::AudacityProject(wxWindow * parent, wxWindowID id,
 #endif
 
    AttachedObjects::BuildAll();
+   // But not for the attached windows.  They get built only on demand, such as
+   // from menu items.
 }
 
 AudacityProject::~AudacityProject()
@@ -2479,14 +2476,6 @@ void AudacityProject::OnCloseWindow(wxCloseEvent & event)
       return;
    }
 
-   // TODO: consider postponing these steps until after the possible veto
-   // below:  closing the two analysis dialogs, and stopping audio streams.
-   // Streams can be for play, recording, or monitoring.  But maybe it still
-   // makes sense to stop any recording before putting up the dialog.
-
-   mFreqWindow.reset();
-   mContrastDialog.reset();
-
    // Check to see if we were playing or recording
    // audio, and if so, make sure Audio I/O is completely finished.
    // The main point of this is to properly push the state
@@ -2590,16 +2579,6 @@ void AudacityProject::OnCloseWindow(wxCloseEvent & event)
 
    projectFileIO.CloseLock();
 
-   // Get rid of the history window
-   // LL:  Destroy it before the TrackPanel and ToolBars since they
-   //      may/will get additional wxEVT_PAINT events since window
-   //      destruction may be queued.  This seems to only be a problem
-   //      on the Mac.
-   if (mHistoryWindow) {
-      mHistoryWindow->Destroy();
-      mHistoryWindow = NULL;
-   }
-
    // Some of the AdornedRulerPanel functions refer to the TrackPanel, so destroy this
    // before the TrackPanel is destroyed. This change was needed to stop Audacity
    // crashing when running with Jaws on Windows 10 1703.
@@ -5507,64 +5486,6 @@ void AudacityProject::PlaybackScroller::OnTimer(wxCommandEvent &event)
    }
 }
 
-LyricsWindow* AudacityProject::GetLyricsWindow(bool create)
-{
-   if (create && !mLyricsWindow)
-      mLyricsWindow = safenew LyricsWindow{ this };
-   return mLyricsWindow;
-}
-
-MixerBoardFrame* AudacityProject::GetMixerBoardFrame(bool create)
-{
-   if (create && !mMixerBoardFrame)
-      mMixerBoardFrame = safenew MixerBoardFrame{ this };
-   return mMixerBoardFrame;
-}
-
-HistoryWindow *AudacityProject::GetHistoryWindow(bool create)
-{
-   auto &project = *this;
-   auto &undoManager = UndoManager::Get( project );
-   if (create && !mHistoryWindow)
-      mHistoryWindow = safenew HistoryWindow{ this, &undoManager };
-   return mHistoryWindow;
-}
-
-MacrosWindow *AudacityProject::GetMacrosWindow(bool bExpanded, bool create)
-{
-   if (create && !mMacrosWindow)
-      mMacrosWindow = safenew MacrosWindow{ this, bExpanded };
-
-   if (mMacrosWindow) {
-      mMacrosWindow->Show();
-      mMacrosWindow->Raise();
-      mMacrosWindow->UpdateDisplay( bExpanded );
-   }
-   return mMacrosWindow;
-}
-
-FreqWindow *AudacityProject::GetFreqWindow(bool create)
-{
-   if (create && !mFreqWindow)
-      mFreqWindow.reset( safenew FreqWindow{
-         this, -1, _("Frequency Analysis"),
-         wxPoint{ 150, 150 }
-      } );
-   return mFreqWindow.get();
-}
-
-ContrastDialog *AudacityProject::GetContrastDialog(bool create)
-{
-   // All of this goes away when the Contrast Dialog is converted to a module
-   if(create && !mContrastDialog)
-      mContrastDialog.reset( safenew ContrastDialog{
-         this, -1, _("Contrast Analysis (WCAG 2 compliance)"),
-         wxPoint{ 150, 150 }
-      } );
-
-   return mContrastDialog.get();
-}
-
 void AudacityProject::ZoomInByFactor( double ZoomFactor )
 {
    auto &project = *this;
diff --git a/src/Project.h b/src/Project.h
index 364d890e3..73925ff16 100644
--- a/src/Project.h
+++ b/src/Project.h
@@ -61,7 +61,6 @@ class TrackList;
 
 class TrackPanel;
 class FreqWindow;
-class ContrastDialog;
 class MeterPanel;
 
 // toolbar classes
@@ -76,11 +75,7 @@ class TranscriptionToolBar;
 
 // windows and frames
 class AdornedRulerPanel;
-class HistoryWindow;
-class MacrosWindow;
 class LyricsWindow;
-class MixerBoard;
-class MixerBoardFrame;
 
 struct AudioIOStartStreamOptions;
 struct UndoState;
@@ -166,9 +161,17 @@ class WaveTrack;
 
 class MenuManager;
 
+// Container of various objects associated with the project, which is
+// responsible for destroying them
 using AttachedObjects = ClientData::Site<
    AudacityProject, ClientData::Base, ClientData::SkipCopying, std::shared_ptr
 >;
+// Container of pointers to various windows associated with the project, which
+// is not responsible for destroying them -- wxWidgets handles that instead
+using AttachedWindows = ClientData::Site<
+   AudacityProject, wxWindow, ClientData::SkipCopying, wxWeakRef
+>;
+
 class AUDACITY_DLL_API AudacityProject final : public wxFrame,
                                      public TrackPanelListener,
                                      public SelectionBarListener,
@@ -177,9 +180,11 @@ class AUDACITY_DLL_API AudacityProject final : public wxFrame,
                                      public AudioIOListener,
                                      private PrefsListener
    , public AttachedObjects
+   , public AttachedWindows
 {
  public:
    using AttachedObjects = ::AttachedObjects;
+   using AttachedWindows = ::AttachedWindows;
 
    AudacityProject(wxWindow * parent, wxWindowID id,
                    const wxPoint & pos, const wxSize & size);
@@ -435,13 +440,6 @@ public:
    MeterPanel *GetCaptureMeter();
    void SetCaptureMeter(MeterPanel *capture);
 
-   LyricsWindow* GetLyricsWindow(bool create = false);
-   MixerBoardFrame* GetMixerBoardFrame(bool create = false);
-   HistoryWindow *GetHistoryWindow(bool create = false);
-   MacrosWindow *GetMacrosWindow(bool bExpanded, bool create = false);
-   FreqWindow *GetFreqWindow(bool create = false);
-   ContrastDialog *GetContrastDialog(bool create = false);
-
 private:
    bool SnapSelection();
 
@@ -562,14 +560,6 @@ private:
    bool mActive{ true };
    bool mIconized;
 
-   MacrosWindow *mMacrosWindow{};
-   HistoryWindow *mHistoryWindow{};
-   LyricsWindow* mLyricsWindow{};
-   MixerBoardFrame* mMixerBoardFrame{};
-
-   Destroy_ptr<FreqWindow> mFreqWindow;
-   Destroy_ptr<ContrastDialog> mContrastDialog;
-
    bool mShownOnce{ false };
 
    // Project owned meters
diff --git a/src/menus/PluginMenus.cpp b/src/menus/PluginMenus.cpp
index e53866fce..fc7fb6c5b 100644
--- a/src/menus/PluginMenus.cpp
+++ b/src/menus/PluginMenus.cpp
@@ -23,6 +23,32 @@
 // private helper classes and functions
 namespace {
 
+AudacityProject::AttachedWindows::RegisteredFactory sContrastDialogKey{
+   []( AudacityProject &parent ) -> wxWeakRef< wxWindow > {
+      return safenew ContrastDialog(
+         &parent, -1, _("Contrast Analysis (WCAG 2 compliance)"),
+         wxPoint{ 150, 150 }
+      );
+   }
+};
+
+AudacityProject::AttachedWindows::RegisteredFactory sFrequencyWindowKey{
+   []( AudacityProject &parent ) -> wxWeakRef< wxWindow > {
+      return safenew FreqWindow(
+         &parent, -1, _("Frequency Analysis"),
+         wxPoint{ 150, 150 }
+      );
+   }
+};
+
+AudacityProject::AttachedWindows::RegisteredFactory sMacrosWindowKey{
+   []( AudacityProject &parent ) -> wxWeakRef< wxWindow > {
+      return safenew MacrosWindow(
+         &parent, true
+      );
+   }
+};
+
 void DoManagePluginsMenu
 (AudacityProject &project, EffectType type)
 {
@@ -591,8 +617,8 @@ void OnManageAnalyzers(const CommandContext &context)
 void OnContrast(const CommandContext &context)
 {
    auto &project = context.project;
-   auto contrastDialog = project.GetContrastDialog(true);
-
+   auto contrastDialog =
+      &project.AttachedWindows::Get< ContrastDialog >( sContrastDialogKey );
 
    contrastDialog->CentreOnParent();
    if( ScreenshotCommand::MayCapture( contrastDialog ) )
@@ -603,8 +629,8 @@ void OnContrast(const CommandContext &context)
 void OnPlotSpectrum(const CommandContext &context)
 {
    auto &project = context.project;
-   auto freqWindow = project.GetFreqWindow(true);
-
+   auto freqWindow =
+      &project.AttachedWindows::Get< FreqWindow >( sFrequencyWindowKey );
 
    if( ScreenshotCommand::MayCapture( freqWindow ) )
       return;
@@ -622,13 +648,25 @@ void OnManageTools(const CommandContext &context )
 void OnManageMacros(const CommandContext &context )
 {
    auto &project = context.project;
-   project.GetMacrosWindow( true, true );
+   auto macrosWindow =
+      &project.AttachedWindows::Get< MacrosWindow >( sMacrosWindowKey );
+   if (macrosWindow) {
+      macrosWindow->Show();
+      macrosWindow->Raise();
+      macrosWindow->UpdateDisplay( true );
+   }
 }
 
 void OnApplyMacrosPalette(const CommandContext &context )
 {
    auto &project = context.project;
-   project.GetMacrosWindow( false, true );
+   auto macrosWindow =
+      &project.AttachedWindows::Get< MacrosWindow >( sMacrosWindowKey );
+   if (macrosWindow) {
+      macrosWindow->Show();
+      macrosWindow->Raise();
+      macrosWindow->UpdateDisplay( false );
+   }
 }
 
 void OnScreenshot(const CommandContext &WXUNUSED(context) )
diff --git a/src/menus/ViewMenus.cpp b/src/menus/ViewMenus.cpp
index 237629619..76acacc7d 100644
--- a/src/menus/ViewMenus.cpp
+++ b/src/menus/ViewMenus.cpp
@@ -8,6 +8,7 @@
 #include "../Prefs.h"
 #include "../Project.h"
 #include "../TrackPanel.h"
+#include "../UndoManager.h"
 #include "../ViewInfo.h"
 #include "../commands/CommandContext.h"
 #include "../commands/CommandManager.h"
@@ -23,6 +24,25 @@
 // private helper classes and functions
 namespace {
 
+AudacityProject::AttachedWindows::RegisteredFactory sMixerBoardKey{
+   []( AudacityProject &parent ) -> wxWeakRef< wxWindow > {
+      return safenew MixerBoardFrame( &parent );
+   }
+};
+
+AudacityProject::AttachedWindows::RegisteredFactory sHistoryWindowKey{
+   []( AudacityProject &parent ) -> wxWeakRef< wxWindow > {
+      auto &undoManager = UndoManager::Get( parent );
+      return safenew HistoryWindow( &parent, &undoManager );
+   }
+};
+
+AudacityProject::AttachedWindows::RegisteredFactory sLyricsWindowKey{
+   []( AudacityProject &parent ) -> wxWeakRef< wxWindow > {
+      return safenew LyricsWindow( &parent );
+   }
+};
+
 double GetZoomOfSelection( const AudacityProject &project )
 {
    auto &viewInfo = ViewInfo::Get( project );
@@ -323,7 +343,7 @@ void OnHistory(const CommandContext &context)
 {
    auto &project = context.project;
 
-   auto historyWindow = project.GetHistoryWindow(true);
+   auto historyWindow = &project.AttachedWindows::Get( sHistoryWindowKey );
    historyWindow->Show();
    historyWindow->Raise();
 }
@@ -332,7 +352,7 @@ void OnKaraoke(const CommandContext &context)
 {
    auto &project = context.project;
 
-   auto lyricsWindow = project.GetLyricsWindow(true);
+   auto lyricsWindow = &project.AttachedWindows::Get( sLyricsWindowKey );
    lyricsWindow->Show();
    lyricsWindow->Raise();
 }
@@ -341,7 +361,7 @@ void OnMixerBoard(const CommandContext &context)
 {
    auto &project = context.project;
 
-   auto mixerBoardFrame = project.GetMixerBoardFrame(true);
+   auto mixerBoardFrame = &project.AttachedWindows::Get( sMixerBoardKey );
    mixerBoardFrame->Show();
    mixerBoardFrame->Raise();
    mixerBoardFrame->SetFocus();