diff --git a/src/BatchProcessDialog.cpp b/src/BatchProcessDialog.cpp
index 9716cb180..b9e575d28 100644
--- a/src/BatchProcessDialog.cpp
+++ b/src/BatchProcessDialog.cpp
@@ -42,6 +42,7 @@
 #include "../images/Arrow.xpm"
 #include "../images/Empty9x16.xpm"
 #include "BatchCommands.h"
+#include "Track.h"
 #include "UndoManager.h"
 
 #include "Theme.h"
diff --git a/src/HistoryWindow.cpp b/src/HistoryWindow.cpp
index 86db27bc3..9f9c6c48e 100644
--- a/src/HistoryWindow.cpp
+++ b/src/HistoryWindow.cpp
@@ -36,6 +36,7 @@ undo memory so as to free up space.
 #include "UndoManager.h"
 #include "Project.h"
 #include "ShuttleGui.h"
+#include "Track.h"
 
 enum {
    ID_AVAIL = 1000,
diff --git a/src/LabelTrack.cpp b/src/LabelTrack.cpp
index aa57b6a1a..c461a4a61 100644
--- a/src/LabelTrack.cpp
+++ b/src/LabelTrack.cpp
@@ -58,6 +58,7 @@ for drawing different aspects of the label and its text box.
 #include "Project.h"
 #include "TrackArtist.h"
 #include "TrackPanel.h"
+#include "UndoManager.h"
 #include "commands/CommandManager.h"
 
 #include "effects/TimeWarper.h"
diff --git a/src/Menus.cpp b/src/Menus.cpp
index 202f51dce..8630da05e 100644
--- a/src/Menus.cpp
+++ b/src/Menus.cpp
@@ -119,6 +119,7 @@ simplifies construction of menu items.
 
 #include "Snap.h"
 
+#include "UndoManager.h"
 #include "WaveTrack.h"
 
 #if defined(EXPERIMENTAL_CRASH_REPORT)
@@ -1598,10 +1599,10 @@ void AudacityProject::CreateRecentFilesMenu(CommandManager *c)
 void AudacityProject::ModifyUndoMenuItems()
 {
    wxString desc;
-   int cur = mUndoManager.GetCurrentState();
+   int cur = GetUndoManager()->GetCurrentState();
 
-   if (mUndoManager.UndoAvailable()) {
-      mUndoManager.GetShortDescription(cur, &desc);
+   if (GetUndoManager()->UndoAvailable()) {
+      GetUndoManager()->GetShortDescription(cur, &desc);
       mCommandManager.Modify(wxT("Undo"),
                              wxString::Format(_("&Undo %s"),
                                               desc.c_str()));
@@ -1611,8 +1612,8 @@ void AudacityProject::ModifyUndoMenuItems()
                              wxString::Format(_("&Undo")));
    }
 
-   if (mUndoManager.RedoAvailable()) {
-      mUndoManager.GetShortDescription(cur+1, &desc);
+   if (GetUndoManager()->RedoAvailable()) {
+      GetUndoManager()->GetShortDescription(cur+1, &desc);
       mCommandManager.Modify(wxT("Redo"),
                              wxString::Format(_("&Redo %s"),
                                               desc.c_str()));
@@ -1756,16 +1757,16 @@ wxUint32 AudacityProject::GetUpdateFlags()
    if((msClipT1 - msClipT0) > 0.0)
       flags |= ClipboardFlag;
 
-   if (mUndoManager.UnsavedChanges())
+   if (GetUndoManager()->UnsavedChanges())
       flags |= UnsavedChangesFlag;
 
    if (!mLastEffect.IsEmpty())
       flags |= HasLastEffectFlag;
 
-   if (mUndoManager.UndoAvailable())
+   if (GetUndoManager()->UndoAvailable())
       flags |= UndoAvailableFlag;
 
-   if (mUndoManager.RedoAvailable())
+   if (GetUndoManager()->RedoAvailable())
       flags |= RedoAvailableFlag;
 
    if (ZoomInAvailable() && (flags & TracksExistFlag))
@@ -3761,7 +3762,7 @@ void AudacityProject::OnPrint()
 
 void AudacityProject::OnUndo()
 {
-   if (!mUndoManager.UndoAvailable()) {
+   if (!GetUndoManager()->UndoAvailable()) {
       wxMessageBox(_("Nothing to undo"));
       return;
    }
@@ -3771,7 +3772,7 @@ void AudacityProject::OnUndo()
       return;
    }
 
-   TrackList *l = mUndoManager.Undo(&mViewInfo.selectedRegion);
+   TrackList *l = GetUndoManager()->Undo(&mViewInfo.selectedRegion);
    PopState(l);
 
    mTrackPanel->SetFocusedTrack(NULL);
@@ -3787,7 +3788,7 @@ void AudacityProject::OnUndo()
 
 void AudacityProject::OnRedo()
 {
-   if (!mUndoManager.RedoAvailable()) {
+   if (!GetUndoManager()->RedoAvailable()) {
       wxMessageBox(_("Nothing to redo"));
       return;
    }
@@ -3796,7 +3797,7 @@ void AudacityProject::OnRedo()
       return;
    }
 
-   TrackList *l = mUndoManager.Redo(&mViewInfo.selectedRegion);
+   TrackList *l = GetUndoManager()->Redo(&mViewInfo.selectedRegion);
    PopState(l);
 
    mTrackPanel->SetFocusedTrack(NULL);
@@ -5262,7 +5263,7 @@ void AudacityProject::OnShowClipping()
 void AudacityProject::OnHistory()
 {
    if (!mHistoryWindow)
-      mHistoryWindow = new HistoryWindow(this, &mUndoManager);
+      mHistoryWindow = new HistoryWindow(this, GetUndoManager());
    mHistoryWindow->Show();
    mHistoryWindow->Raise();
    mHistoryWindow->UpdateDisplay();
diff --git a/src/MixerBoard.cpp b/src/MixerBoard.cpp
index 22c1eff28..a94da18ad 100644
--- a/src/MixerBoard.cpp
+++ b/src/MixerBoard.cpp
@@ -27,6 +27,7 @@
 #endif
 #include "Project.h"
 #include "TrackPanel.h" // for EVT_TRACK_PANEL_TIMER
+#include "UndoManager.h"
 #include "WaveTrack.h"
 
 #include "widgets/Meter.h"
diff --git a/src/Project.cpp b/src/Project.cpp
index 211b1afdd..b502034eb 100644
--- a/src/Project.cpp
+++ b/src/Project.cpp
@@ -143,6 +143,8 @@ scroll information.  It also has some status flags.
 
 #include "FileDialog.h"
 
+#include "UndoManager.h"
+
 #include "toolbars/ToolManager.h"
 #include "toolbars/ControlToolBar.h"
 #include "toolbars/DeviceToolBar.h"
@@ -796,6 +798,7 @@ AudacityProject::AudacityProject(wxWindow * parent, wxWindowID id,
      mSelectionFormat(gPrefs->Read(wxT("/SelectionFormat"), wxT(""))),
      mFrequencySelectionFormatName(gPrefs->Read(wxT("/FrequencySelectionFormatName"), wxT(""))),
      mBandwidthSelectionFormatName(gPrefs->Read(wxT("/BandwidthSelectionFormatName"), wxT(""))),
+     mUndoManager(safenew UndoManager),
      mDirty(false),
      mRuler(NULL),
      mTrackPanel(NULL),
@@ -2211,7 +2214,7 @@ void AudacityProject::OnCloseWindow(wxCloseEvent & event)
    // We may not bother to prompt the user to save, if the
    // project is now empty.
    if (event.CanVeto() && (mEmptyCanBeDirty || bHasTracks)) {
-      if (mUndoManager.UnsavedChanges()) {
+      if (GetUndoManager()->UnsavedChanges()) {
 
          wxString Message = _("Save changes before closing?");
          if( !bHasTracks )
@@ -2336,7 +2339,7 @@ void AudacityProject::OnCloseWindow(wxCloseEvent & event)
 
    // This must be done before the following Deref() since it holds
    // references to the DirManager.
-   mUndoManager.ClearStates();
+   GetUndoManager()->ClearStates();
 
    // MM: Tell the DirManager it can now DELETE itself
    // if it finds it is no longer needed. If it is still
@@ -3411,7 +3414,7 @@ bool AudacityProject::Save(bool overwrite /* = true */ ,
       bool bHasTracks = (iter.First() != NULL);
       if (!bHasTracks)
       {
-         if (mUndoManager.UnsavedChanges() && mEmptyCanBeDirty) {
+         if (GetUndoManager()->UnsavedChanges() && mEmptyCanBeDirty) {
             int result = wxMessageBox(_("Your project is now empty.\nIf saved, the project will have no tracks.\n\nTo save any previously open tracks:\nClick 'No', Edit > Undo until all tracks\nare open, then File > Save Project.\n\nSave anyway?"),
                                       _("Warning - Empty Project"),
                                       wxYES_NO | wxICON_QUESTION, this);
@@ -3596,7 +3599,7 @@ bool AudacityProject::Save(bool overwrite /* = true */ ,
          t = iter.Next();
       }
 
-      mUndoManager.StateSaved();
+      GetUndoManager()->StateSaved();
    }
 
    // If we get here, saving the project was successful, so we can DELETE
@@ -3979,12 +3982,12 @@ void AudacityProject::InitialState()
       mImportXMLTagHandler = NULL;
    }
 
-   mUndoManager.ClearStates();
+   GetUndoManager()->ClearStates();
 
-   mUndoManager.PushState(mTracks, mViewInfo.selectedRegion,
+   GetUndoManager()->PushState(mTracks, mViewInfo.selectedRegion,
                           _("Created new project"), wxT(""));
 
-   mUndoManager.StateSaved();
+   GetUndoManager()->StateSaved();
 
    if (mHistoryWindow)
       mHistoryWindow->UpdateDisplay();
@@ -3996,11 +3999,16 @@ void AudacityProject::InitialState()
    this->UpdateMixerBoard();
 }
 
+void AudacityProject::PushState(const wxString &desc, const wxString &shortDesc)
+{
+   PushState(desc, shortDesc, PUSH_AUTOSAVE);
+}
+
 void AudacityProject::PushState(const wxString &desc,
                                 const wxString &shortDesc,
                                 int flags )
 {
-   mUndoManager.PushState(mTracks, mViewInfo.selectedRegion,
+   GetUndoManager()->PushState(mTracks, mViewInfo.selectedRegion,
                           desc, shortDesc, flags);
 
    mDirty = true;
@@ -4036,7 +4044,7 @@ void AudacityProject::RollbackState()
 
 void AudacityProject::ModifyState(bool bWantsAutoSave)
 {
-   mUndoManager.ModifyState(mTracks, mViewInfo.selectedRegion);
+   GetUndoManager()->ModifyState(mTracks, mViewInfo.selectedRegion);
    if (bWantsAutoSave)
       AutoSave();
 }
@@ -4097,7 +4105,7 @@ void AudacityProject::PopState(TrackList * l)
 void AudacityProject::SetStateTo(unsigned int n)
 {
    TrackList *l =
-       mUndoManager.SetStateTo(n, &mViewInfo.selectedRegion);
+       GetUndoManager()->SetStateTo(n, &mViewInfo.selectedRegion);
    PopState(l);
 
    HandleResize();
diff --git a/src/Project.h b/src/Project.h
index 4dbca4d7b..6d164d943 100644
--- a/src/Project.h
+++ b/src/Project.h
@@ -22,7 +22,6 @@
 #include "Experimental.h"
 
 #include "DirManager.h"
-#include "UndoManager.h"
 #include "ViewInfo.h"
 #include "TrackPanelListener.h"
 #include "AudioIOListener.h"
@@ -90,6 +89,7 @@ class WaveTrackArray;
 class Regions;
 
 class LWSlider;
+class UndoManager;
 
 AudacityProject *CreateNewAudacityProject();
 AUDACITY_DLL_API AudacityProject *GetActiveProject();
@@ -157,7 +157,7 @@ class AUDACITY_DLL_API AudacityProject:  public wxFrame,
    AudioIOStartStreamOptions GetDefaultPlayOptions();
 
    TrackList *GetTracks() { return mTracks; }
-   UndoManager *GetUndoManager() { return &mUndoManager; }
+   UndoManager *GetUndoManager() { return mUndoManager.get(); }
 
    sampleFormat GetDefaultFormat() { return mDefaultFormat; }
 
@@ -486,8 +486,8 @@ public:
    static void AllProjectsDeleteLock();
    static void AllProjectsDeleteUnlock();
 
-   void PushState(const wxString &desc, const wxString &shortDesc,
-                  int flags = PUSH_AUTOSAVE);
+   void PushState(const wxString &desc, const wxString &shortDesc); // use PUSH_AUTOSAVE
+   void PushState(const wxString &desc, const wxString &shortDesc, int flags);
    void RollbackState();
 
  private:
@@ -546,7 +546,7 @@ public:
    static ODLock *msAllProjectDeleteMutex;
 
    // History/Undo manager
-   UndoManager mUndoManager;
+   std::unique_ptr<UndoManager> mUndoManager;
    bool mDirty;
 
    // Commands
diff --git a/src/TrackPanel.cpp b/src/TrackPanel.cpp
index 4f81031fd..ed2d23610 100644
--- a/src/TrackPanel.cpp
+++ b/src/TrackPanel.cpp
@@ -181,6 +181,7 @@ is time to refresh some aspect of the screen.
 #include "TimeTrack.h"
 #include "TrackArtist.h"
 #include "TrackPanelAx.h"
+#include "UndoManager.h"
 #include "WaveTrack.h"
 
 #include "commands/Keyboard.h"
@@ -1497,6 +1498,11 @@ void TrackPanel::MakeParentPushState(const wxString &desc, const wxString &short
    mListener->TP_PushState(desc, shortDesc, flags);
 }
 
+void TrackPanel::MakeParentPushState(const wxString &desc, const wxString &shortDesc)
+{
+   MakeParentPushState(desc, shortDesc, PUSH_AUTOSAVE);
+}
+
 void TrackPanel::MakeParentModifyState(bool bWantsAutoSave)
 {
    mListener->TP_ModifyState(bWantsAutoSave);
diff --git a/src/TrackPanel.h b/src/TrackPanel.h
index dbe95eac2..c784a8055 100644
--- a/src/TrackPanel.h
+++ b/src/TrackPanel.h
@@ -21,9 +21,9 @@
 
 #include "Experimental.h"
 #include "audacity/Types.h"
-#include "UndoManager.h" //JKC: Included for PUSH_XXX definitions.
 #include "widgets/NumericTextCtrl.h"
 
+#include "SelectedRegion.h"
 #include "WaveTrackLocation.h"
 
 #include "Snap.h"
@@ -457,8 +457,9 @@ protected:
    virtual void MakeParentRedrawScrollbars();
 
    // AS: Pushing the state preserves state for Undo operations.
+   virtual void MakeParentPushState(const wxString &desc, const wxString &shortDesc); // use PUSH_AUTOSAVE
    virtual void MakeParentPushState(const wxString &desc, const wxString &shortDesc,
-                            int flags = PUSH_AUTOSAVE);
+                            int flags);
    virtual void MakeParentModifyState(bool bWantsAutoSave);    // if true, writes auto-save file. Should set only if you really want the state change restored after
                                                                // a crash, as it can take many seconds for large (eg. 10 track-hours) projects
 
diff --git a/src/TrackPanelListener.h b/src/TrackPanelListener.h
index 15385957e..f07c2b11f 100644
--- a/src/TrackPanelListener.h
+++ b/src/TrackPanelListener.h
@@ -26,7 +26,7 @@ class AUDACITY_DLL_API TrackPanelListener {
    virtual ToolsToolBar * TP_GetToolsToolBar() = 0;
 
    virtual void TP_PushState(const wxString &shortDesc, const wxString &longDesc,
-                            int flags = PUSH_AUTOSAVE) = 0;
+                            int flags) = 0;
    virtual void TP_ModifyState(bool bWantsAutoSave) = 0;    // if true, writes auto-save file. Should set only if you really want the state change restored after
                                                             // a crash, as it can take many seconds for large (eg. 10 track-hours) projects
    virtual void TP_RedrawScrollbars() = 0;
diff --git a/src/ondemand/ODTask.cpp b/src/ondemand/ODTask.cpp
index 774118b67..af6ef52f1 100644
--- a/src/ondemand/ODTask.cpp
+++ b/src/ondemand/ODTask.cpp
@@ -22,6 +22,7 @@ in a background thread.
 #include "ODManager.h"
 #include "../WaveTrack.h"
 #include "../Project.h"
+#include "../UndoManager.h"
 //temporarilly commented out till it is added to all projects
 //#include "../Profiler.h"