diff --git a/src/Envelope.cpp b/src/Envelope.cpp
index 7ae799fed..a78d4df0b 100644
--- a/src/Envelope.cpp
+++ b/src/Envelope.cpp
@@ -57,27 +57,19 @@ Envelope::Envelope()
    mDB = true;
    mDefaultValue = 1.0;
    mDragPoint = -1;
-   mDirty = false;
-   mIsDeleting = false;
-   mMirror = true;
 
    mMinValue = 1.0e-7;
    mMaxValue = 2.0;
 
-   mButton = wxMOUSE_BTN_NONE;
-
    mSearchGuess = -1;
+
+   mDragPointValid = false;
 }
 
 Envelope::~Envelope()
 {
 }
 
-void Envelope::Mirror(bool mirror)
-{
-   mMirror = mirror;
-}
-
 /// Rescale function for time tracks (could also be used for other tracks though).
 /// This is used to load old time track project files where the envelope used a 0 to 1
 /// range instead of storing the actual time track values. This function will change the range of the envelope
@@ -112,6 +104,84 @@ void Envelope::Flatten(double value)
    mDefaultValue = ClampValue(value);
 }
 
+void Envelope::SetDragPoint(int dragPoint)
+{
+   mDragPoint = std::max(-1, std::min(int(mEnv.size() - 1), dragPoint));
+   mDragPointValid = (mDragPoint >= 0);
+}
+
+void Envelope::SetDragPointValid(bool valid)
+{
+   mDragPointValid = (valid && mDragPoint >= 0);
+   if (mDragPoint >= 0 && !valid) {
+      // We're going to be deleting the point; On
+      // screen we show this by having the envelope move to
+      // the position it will have after deletion of the point.
+      // Without deleting the point we move it left or right
+      // to the same position as the previous or next point.
+
+      static const double big = std::numeric_limits<double>::max();
+      auto size = mEnv.size();
+
+      if( size <= 1) {
+         // There is only one point - just move it
+         // off screen and at default height.
+         // temporary state when dragging only!
+         mEnv[mDragPoint].SetT(big);
+         mEnv[mDragPoint].SetVal(mDefaultValue);
+         return;
+      }
+      else if ( mDragPoint + 1 == size ) {
+         // Put the point at the height of the last point, but also off screen.
+         mEnv[mDragPoint].SetT(big);
+         mEnv[mDragPoint].SetVal(mEnv[ size - 1 ].GetVal());
+      }
+      else {
+         // Place it exactly on its right neighbour.
+         // That way the drawing code will overpaint the dark dot with
+         // a light dot, as if it were deleted.
+         const auto &neighbor = mEnv[mDragPoint + 1];
+         mEnv[mDragPoint].SetT(neighbor.GetT());
+         mEnv[mDragPoint].SetVal(neighbor.GetVal());
+      }
+   }
+}
+
+void Envelope::MoveDragPoint(double newWhen, double value)
+{
+   SetDragPointValid(true);
+   if (!mDragPointValid)
+      return;
+
+   // We'll limit the drag point time to be between those of the preceding
+   // and next envelope point.
+   double limitLo = 0.0;
+   double limitHi = mTrackLen;
+
+   if (mDragPoint > 0)
+      limitLo = std::max(limitLo, mEnv[mDragPoint - 1].GetT());
+   if (mDragPoint + 1 < mEnv.size())
+      limitHi = std::min(limitHi, mEnv[mDragPoint + 1].GetT());
+
+   EnvPoint &dragPoint = mEnv[mDragPoint];
+   const double tt =
+      std::max(limitLo, std::min(limitHi, newWhen));
+
+   // This might temporary violate the constraint that at most two
+   // points share a time value.
+   dragPoint.SetT(tt);
+   dragPoint.SetVal(value);
+}
+
+void Envelope::ClearDragPoint()
+{
+   if (!mDragPointValid && mDragPoint >= 0)
+      Delete(mDragPoint);
+
+   mDragPoint = -1;
+   mDragPointValid = false;
+}
+
 void Envelope::SetRange(double minValue, double maxValue) {
    mMinValue = minValue;
    mMaxValue = maxValue;
@@ -186,7 +256,7 @@ static void DrawPoint(wxDC & dc, const wxRect & r, int x, int y, bool top)
 /// TODO: This should probably move to track artist.
 void Envelope::DrawPoints(wxDC & dc, const wxRect & r, const ZoomInfo &zoomInfo,
                     bool dB, double dBRange,
-                    float zoomMin, float zoomMax) const
+                    float zoomMin, float zoomMax, bool mirrored) const
 {
    dc.SetPen(AColor::envelopePen);
    dc.SetBrush(*wxWHITE_BRUSH);
@@ -207,7 +277,7 @@ void Envelope::DrawPoints(wxDC & dc, const wxRect & r, const ZoomInfo &zoomInfo,
 
          y = GetWaveYPos(v, zoomMin, zoomMax, r.height, dB,
             true, dBRange, false);
-         if (!mMirror) {
+         if (!mirrored) {
             DrawPoint(dc, r, x, y, true);
          }
          else {
@@ -311,7 +381,7 @@ inline int SQR(int x) { return x * x; }
 /// @dB - display mode either linear or log.
 /// @zoomMin - vertical scale, typically -1.0
 /// @zoomMax - vertical scale, typically +1.0
-float Envelope::ValueOfPixel( int y, int height, bool upper,
+float EnvelopeEditor::ValueOfPixel( int y, int height, bool upper,
                               bool dB, double dBRange,
                               float zoomMin, float zoomMax)
 {
@@ -320,9 +390,9 @@ float Envelope::ValueOfPixel( int y, int height, bool upper,
    // MB: this is mostly equivalent to what the old code did, I'm not sure
    // if anything special is needed for asymmetric ranges
    if(upper)
-      return ClampValue(v);
+      return mEnvelope.ClampValue(v);
    else
-      return ClampValue(-v);
+      return mEnvelope.ClampValue(-v);
 }
 
 /// HandleMouseButtonDown either finds an existing control point or adds a NEW one
@@ -331,13 +401,13 @@ float Envelope::ValueOfPixel( int y, int height, bool upper,
 /// a given time value:
 /// We have an upper and lower envelope line.
 /// Also we may be showing an inner envelope (at 0.5 the range).
-bool Envelope::HandleMouseButtonDown(const wxMouseEvent & event, wxRect & r,
+bool EnvelopeEditor::HandleMouseButtonDown(const wxMouseEvent & event, wxRect & r,
                                      const ZoomInfo &zoomInfo,
                                      bool dB, double dBRange,
                                      float zoomMin, float zoomMax)
 {
    int ctr = (int)(r.height * zoomMax / (zoomMax - zoomMin));
-   bool upper = !mMirror || (zoomMin >= 0.0) || (event.m_y - r.y < ctr);
+   bool upper = !mMirrored || (zoomMin >= 0.0) || (event.m_y - r.y < ctr);
 
    int clip_y = event.m_y - r.y;
    if(clip_y < 0) clip_y = 0; //keeps point in rect r, even if mouse isn't
@@ -348,16 +418,15 @@ bool Envelope::HandleMouseButtonDown(const wxMouseEvent & event, wxRect & r,
 
    // Member variables hold state that will be needed in dragging.
    mButton        = event.GetButton();
-   mIsDeleting    = false;
    mContourOffset = false;
 
    //   wxLogDebug(wxT("Y:%i Height:%i Offset:%i"), y, height, mContourOffset );
-   int len = mEnv.size();
+   int len = mEnvelope.GetNumberOfPoints();
 
    // TODO: extract this into a function FindNearestControlPoint()
    // TODO: also fix it so that we can drag the last point on an envelope.
    for (int i = 0; i < len; i++) { //search for control point nearest click
-      const double time = mEnv[i].GetT() + mOffset;
+      const double time = mEnvelope[i].GetT() + mEnvelope.GetOffset();
       const wxInt64 position = zoomInfo.TimeToPosition(time);
       if (position >= 0 && position < r.width) {
 
@@ -366,7 +435,7 @@ bool Envelope::HandleMouseButtonDown(const wxMouseEvent & event, wxRect & r,
          int numControlPoints;
 
          // Outer control points
-         double value = mEnv[i].GetVal();
+         double value = mEnvelope[i].GetVal();
          y[0] = GetWaveYPos(value, zoomMin, zoomMax, r.height,
                                 dB, true, dBRange, false);
          y[1] = GetWaveYPos(-value, zoomMin, zoomMax, r.height,
@@ -383,7 +452,7 @@ bool Envelope::HandleMouseButtonDown(const wxMouseEvent & event, wxRect & r,
          if (y[2] > y[3])
             numControlPoints = 2;
 
-         if (!mMirror)
+         if (!mMirrored)
             numControlPoints = 1;
 
          const int deltaXSquared = SQR(x - (event.m_x - r.x));
@@ -400,7 +469,7 @@ bool Envelope::HandleMouseButtonDown(const wxMouseEvent & event, wxRect & r,
    }
 
    if (bestNum >= 0) {
-      mDragPoint = bestNum;
+      mEnvelope.SetDragPoint(bestNum);
    }
    else {
       // TODO: Extract this into a function CreateNewPoint
@@ -409,13 +478,13 @@ bool Envelope::HandleMouseButtonDown(const wxMouseEvent & event, wxRect & r,
       //      if (when <= 0 || when >= mTrackLen)
       //         return false;
 
-      const double v = GetValue( when );
+      const double v = mEnvelope.GetValue( when );
 
       int ct = GetWaveYPos( v, zoomMin, zoomMax, r.height, dB,
                                false, dBRange, false) ;
       int cb = GetWaveYPos( -v-.000000001, zoomMin, zoomMax, r.height, dB,
                                false, dBRange, false) ;
-      if( ct <= cb || !mMirror ){
+      if (ct <= cb || !mMirrored) {
          int t = GetWaveYPos( v, zoomMin, zoomMax, r.height, dB,
                                  true, dBRange, false) ;
          int b = GetWaveYPos( -v, zoomMin, zoomMax, r.height, dB,
@@ -424,7 +493,7 @@ bool Envelope::HandleMouseButtonDown(const wxMouseEvent & event, wxRect & r,
          ct = (t + ct) / 2;
          cb = (b + cb) / 2;
 
-         if(mMirror &&
+         if (mMirrored &&
             (event.m_y - r.y) > ct &&
             ((event.m_y - r.y) < cb))
             mContourOffset = true;
@@ -435,50 +504,22 @@ bool Envelope::HandleMouseButtonDown(const wxMouseEvent & event, wxRect & r,
       double newVal = ValueOfPixel(clip_y, r.height, upper, dB, dBRange,
                                    zoomMin, zoomMax);
 
-      mDragPoint = Insert(when - mOffset, newVal);
+      mEnvelope.SetDragPoint(mEnvelope.Insert(when - mEnvelope.GetOffset(), newVal));
       mDirty = true;
    }
 
    mUpper = upper;
 
-   mInitialVal = mEnv[mDragPoint].GetVal();
-
-   mInitialY = event.m_y+mContourOffset;
+   // const int dragPoint = mEnvelope.GetDragPoint();
+   // mInitialVal = mEnvelope[dragPoint].GetVal();
+   // mInitialY = event.m_y+mContourOffset;
 
    return true;
 }
 
-/// Mark dragged point for deletion.
-/// It will be deleted on mouse button up.
-void Envelope::MarkDragPointForDeletion()
-{
-   mIsDeleting = true;
-
-   // We're going to be deleting the point; On
-   // screen we show this by having the envelope move to
-   // the position it will have after deletion of the point.
-   // Without delting the point we move it left or right
-   // to the same position as the previous or next point.
-
-   if( mEnv.size() <= 1)
-   {
-      // There is only one point - just move it
-      // off screen and at default height.
-      // temporary state when dragging only!
-      mEnv[mDragPoint].SetT(-1000000.0);
-      mEnv[mDragPoint].SetVal(mDefaultValue);
-      return;
-   }
-
-   // Place it exactly on one of its neighbours.
-   int iNeighbourPoint = mDragPoint + ((mDragPoint > 0) ? -1:+1);
-   mEnv[mDragPoint].SetT(mEnv[iNeighbourPoint].GetT());
-   mEnv[mDragPoint].SetVal(mEnv[iNeighbourPoint].GetVal());
-}
-
-void Envelope::MoveDraggedPoint( const wxMouseEvent & event, wxRect & r,
-                                 const ZoomInfo &zoomInfo, bool dB, double dBRange,
-                                 float zoomMin, float zoomMax)
+void EnvelopeEditor::MoveDragPoint(const wxMouseEvent & event, wxRect & r,
+                               const ZoomInfo &zoomInfo, bool dB, double dBRange,
+                               float zoomMin, float zoomMax)
 {
    int clip_y = event.m_y - r.y;
    if(clip_y < 0) clip_y = 0;
@@ -491,29 +532,14 @@ void Envelope::MoveDraggedPoint( const wxMouseEvent & event, wxRect & r,
    // TODO: However because mTrackEpsilon assumes 200KHz this use
    // of epsilon is a tad bogus.  What we need to do instead is DELETE
    // a duplicated point on a mouse up.
-   double newWhen = zoomInfo.PositionToTime(event.m_x, r.x) - mOffset;
-
-   // We'll limit the drag point time to be between those of the preceding
-   // and next envelope point.
-   double limitLo = 0.0;
-   double limitHi = mTrackLen;
-
-   if (mDragPoint > 0)
-      limitLo = mEnv[mDragPoint - 1].GetT() + mTrackEpsilon;
-   if (mDragPoint < (int)mEnv.size() - 1 )
-      limitHi = mEnv[mDragPoint + 1].GetT() - mTrackEpsilon;
-
-   newWhen = Limit( limitLo, newWhen, limitHi );
-   newWhen = Limit( mTrackEpsilon, newWhen, mTrackLen - mTrackEpsilon);
-
-   mEnv[mDragPoint].SetT(newWhen);
-   mEnv[mDragPoint].SetVal(newVal);
-
+   double newWhen = zoomInfo.PositionToTime(event.m_x, r.x) - mEnvelope.GetOffset();
+   mEnvelope.MoveDragPoint(newWhen, newVal);
 }
 
-bool Envelope::HandleDragging( const wxMouseEvent & event, wxRect & r,
+bool EnvelopeEditor::HandleDragging(const wxMouseEvent & event, wxRect & r,
                                const ZoomInfo &zoomInfo, bool dB, double dBRange,
-                               float zoomMin, float zoomMax)
+                               float zoomMin, float zoomMax,
+                               float WXUNUSED(eMin), float WXUNUSED(eMax))
 {
    mDirty = true;
 
@@ -523,27 +549,24 @@ bool Envelope::HandleDragging( const wxMouseEvent & event, wxRect & r,
    if (larger.Contains(event.m_x, event.m_y))
    {
       // IF we're in the rect THEN we're not deleting this point (anymore).
-      mIsDeleting = false;
       // ...we're dragging it.
-      MoveDraggedPoint( event, r, zoomInfo, dB, dBRange, zoomMin, zoomMax);
+      MoveDragPoint( event, r, zoomInfo, dB, dBRange, zoomMin, zoomMax);
       return true;
    }
 
-   if(mIsDeleting )
+   if(!mEnvelope.GetDragPointValid())
       // IF we already know we're deleting THEN no envelope point to update.
       return false;
 
-   MarkDragPointForDeletion();
+   // Invalidate the point
+   mEnvelope.SetDragPointValid(false);
    return true;
 }
 
-// Exit dragging mode and deletes dragged point if neccessary.
-bool Envelope::HandleMouseButtonUp()
+// Exit dragging mode and delete dragged point if neccessary.
+bool EnvelopeEditor::HandleMouseButtonUp()
 {
-   if (mIsDeleting) {
-      Delete(mDragPoint);
-   }
-   mDragPoint = -1;
+   mEnvelope.ClearDragPoint();
    mButton = wxMOUSE_BTN_NONE;
    return true;
 }
@@ -559,14 +582,14 @@ void Envelope::Insert(int point, const EnvPoint &p)
 }
 
 // Returns true if parent needs to be redrawn
-bool Envelope::MouseEvent(const wxMouseEvent & event, wxRect & r,
+bool EnvelopeEditor::MouseEvent(const wxMouseEvent & event, wxRect & r,
                           const ZoomInfo &zoomInfo, bool dB, double dBRange,
                           float zoomMin, float zoomMax)
 {
    if (event.ButtonDown() && mButton == wxMOUSE_BTN_NONE)
       return HandleMouseButtonDown( event, r, zoomInfo, dB, dBRange,
                                     zoomMin, zoomMax);
-   if (event.Dragging() && mDragPoint >= 0)
+   if (event.Dragging() && mEnvelope.GetDragPoint() >= 0)
       return HandleDragging( event, r, zoomInfo, dB, dBRange,
                              zoomMin, zoomMax);
    if (event.ButtonUp() && event.GetButton() == mButton)
@@ -1523,7 +1546,6 @@ void Envelope::testMe()
    double t0=0, t1=0;
 
    SetInterpolateDB(false);
-   Mirror(false);
 
    Flatten(0.5);
    checkResult( 1, Integral(0.0,100.0), 50);
@@ -1575,3 +1597,18 @@ void Envelope::testMe()
    checkResult( 19, NextPointAfter( 5 ), 10 );
 }
 
+EnvelopeEditor::EnvelopeEditor(Envelope &envelope, bool mirrored)
+   : mEnvelope(envelope)
+   , mMirrored(mirrored)
+   , mContourOffset(-1)
+   // , mInitialVal(-1.0)
+   // , mInitialY(-1)
+   , mUpper(false)
+   , mButton(wxMOUSE_BTN_NONE)
+   , mDirty(false)
+{
+}
+
+EnvelopeEditor::~EnvelopeEditor()
+{
+}
diff --git a/src/Envelope.h b/src/Envelope.h
index 2da8ad7cb..a95222066 100644
--- a/src/Envelope.h
+++ b/src/Envelope.h
@@ -81,13 +81,14 @@ class Envelope final : public XMLTagHandler {
 
    virtual ~ Envelope();
 
+   double GetOffset() const { return mOffset; }
+   double GetTrackLen() const { return mTrackLen; }
+
    bool GetInterpolateDB() { return mDB; }
    void SetInterpolateDB(bool db) { mDB = db; }
-   void Mirror(bool mirror);
    void Rescale(double minValue, double maxValue);
 
    void Flatten(double value);
-   int GetDragPoint(void)   {return mDragPoint;}
 
    double GetMinValue() const { return mMinValue; }
    double GetMaxValue() const { return mMaxValue; }
@@ -107,21 +108,8 @@ class Envelope final : public XMLTagHandler {
    void WriteXML(XMLWriter &xmlFile) const /* not override */;
 
    void DrawPoints(wxDC & dc, const wxRect & r, const ZoomInfo &zoomInfo,
-             bool dB, double dBRange,
-             float zoomMin, float zoomMax) const;
-
-   // Event Handlers
-   // Each ofthese returns true if parents needs to be redrawn
-   bool MouseEvent(const wxMouseEvent & event, wxRect & r,
-                   const ZoomInfo &zoomInfo, bool dB, double dBRange,
-                   float zoomMin, float zoomMax);
-   bool HandleMouseButtonDown( const wxMouseEvent & event, wxRect & r,
-                               const ZoomInfo &zoomInfo, bool dB, double dBRange,
-                               float zoomMin, float zoomMax);
-   bool HandleDragging( const wxMouseEvent & event, wxRect & r,
-                        const ZoomInfo &zoomInfo, bool dB, double dBRange,
-                        float zoomMin, float zoomMax);
-   bool HandleMouseButtonUp();
+      bool dB, double dBRange,
+      float zoomMin, float zoomMax, bool mirrored) const;
 
    // Handling Cut/Copy/Paste events
    void CollapseRegion(double t0, double t1);
@@ -181,28 +169,38 @@ class Envelope final : public XMLTagHandler {
    /** \brief Return number of points */
    size_t GetNumberOfPoints() const;
 
+private:
+   friend class EnvelopeEditor;
    /** \brief Accessor for points */
-   const EnvPoint &operator[] (int index) const
+   EnvPoint &operator[] (int index)
    {
       return mEnv[index];
    }
 
+public:
    /** \brief Returns the sets of when and value pairs */
    void GetPoints(double *bufferWhen,
-                  double *bufferValue,
-                  int bufferLen) const;
+      double *bufferValue,
+      int bufferLen) const;
+
+   // UI-related
+   // The drag point needs to display differently.
+   int GetDragPoint() const { return mDragPoint; }
+   // Choose the drag point.
+   void SetDragPoint(int dragPoint);
+   // Mark or unmark the drag point for deletion.
+   void SetDragPointValid(bool valid);
+   bool GetDragPointValid() const { return mDragPointValid; }
+   // Modify the dragged point and change its value.
+   // But consistency constraints may move it less then you ask for.
+   void MoveDragPoint(double newWhen, double value);
+   // May delete the drag point.  Restores envelope consistency.
+   void ClearDragPoint();
 
 private:
    EnvPoint *  AddPointAtEnd( double t, double val );
-   void MarkDragPointForDeletion();
-   float ValueOfPixel( int y, int height, bool upper,
-                       bool dB, double dBRange,
-                       float zoomMin, float zoomMax);
    void BinarySearchForTime( int &Lo, int &Hi, double t ) const;
    double GetInterpolationStartValueAtPoint( int iPoint ) const;
-   void MoveDraggedPoint( const wxMouseEvent & event, wxRect & r,
-                               const ZoomInfo &zoomInfo, bool dB, double dBRange,
-                               float zoomMin, float zoomMax);
 
    // Possibly inline functions:
    // This function resets them integral memoizers (call whenever the Envelope changes)
@@ -210,7 +208,6 @@ private:
 
    // The list of envelope control points.
    EnvArray mEnv;
-   bool mMirror;
 
    /** \brief The time at which the envelope starts, i.e. the start offset */
    double mOffset;
@@ -224,21 +221,7 @@ private:
     * before being considered the same point */
    double mTrackEpsilon;
    double mDefaultValue;
-
-   /** \brief Number of pixels contour is from the true envelope. */
-   int mContourOffset;
-
-   double mInitialVal;
-
-   // These are used in dragging.
-   int mDragPoint;
-   int mInitialY;
-   bool mUpper;
-   bool mIsDeleting;
-   int mButton;
    bool mDB;
-   bool mDirty;
-
    double mMinValue, mMaxValue;
 
    // These are memoizing variables for Integral()
@@ -246,8 +229,11 @@ private:
    double lastIntegral_t1;
    double lastIntegral_result;
 
-   mutable int mSearchGuess;
+   // UI stuff
+   bool mDragPointValid;
+   int mDragPoint;
 
+   mutable int mSearchGuess;
 };
 
 inline EnvPoint::EnvPoint(Envelope *envelope, double t, double val)
@@ -262,5 +248,49 @@ inline void EnvPoint::SetVal(double val)
    mVal = mEnvelope->ClampValue(val);
 }
 
-#endif
+// A class that holds state for the duration of dragging
+// of an envelope point.
+class EnvelopeEditor
+{
+public:
+   EnvelopeEditor(Envelope &envelope, bool mirrored);
+   ~EnvelopeEditor();
 
+   // Event Handlers
+   // Each of these returns true if the envelope needs to be redrawn
+   bool MouseEvent(const wxMouseEvent & event, wxRect & r,
+      const ZoomInfo &zoomInfo, bool dB, double dBRange,
+      float zoomMin = -1.0, float zoomMax = 1.0);
+
+private:
+   bool HandleMouseButtonDown(const wxMouseEvent & event, wxRect & r,
+      const ZoomInfo &zoomInfo, bool dB, double dBRange,
+      float zoomMin = -1.0, float zoomMax = 1.0);
+   bool HandleDragging(const wxMouseEvent & event, wxRect & r,
+      const ZoomInfo &zoomInfo, bool dB, double dBRange,
+      float zoomMin = -1.0, float zoomMax = 1.0, float eMin = 0., float eMax = 2.);
+   bool HandleMouseButtonUp();
+
+private:
+   float ValueOfPixel(int y, int height, bool upper,
+      bool dB, double dBRange,
+      float zoomMin, float zoomMax);
+   void MoveDragPoint(const wxMouseEvent & event, wxRect & r,
+      const ZoomInfo &zoomInfo, bool dB, double dBRange,
+      float zoomMin, float zoomMax);
+
+   Envelope &mEnvelope;
+   const bool mMirrored;
+
+   /** \brief Number of pixels contour is from the true envelope. */
+   int mContourOffset;
+
+   // double mInitialVal;
+
+   // int mInitialY;
+   bool mUpper;
+   int mButton;
+   bool mDirty;
+};
+
+#endif
diff --git a/src/TimeTrack.cpp b/src/TimeTrack.cpp
index 4be32cfd5..bdfa67d8f 100644
--- a/src/TimeTrack.cpp
+++ b/src/TimeTrack.cpp
@@ -48,7 +48,6 @@ TimeTrack::TimeTrack(const std::shared_ptr<DirManager> &projDirManager, const Zo
    mEnvelope->SetTrackLen(DBL_MAX);
    mEnvelope->SetInterpolateDB(true);
    mEnvelope->Flatten(1.0);
-   mEnvelope->Mirror(false);
    mEnvelope->SetOffset(0);
    mEnvelope->SetRange(TIMETRACK_MIN, TIMETRACK_MAX);
 
@@ -75,7 +74,6 @@ TimeTrack::TimeTrack(const TimeTrack &orig):
    mEnvelope->SetTrackLen(DBL_MAX);
    SetInterpolateLog(orig.GetInterpolateLog()); // this calls Envelope::SetInterpolateDB
    mEnvelope->Flatten(1.0);
-   mEnvelope->Mirror(false);
    mEnvelope->SetOffset(0);
    mEnvelope->SetRange(orig.mEnvelope->GetMinValue(), orig.mEnvelope->GetMaxValue());
    mEnvelope->Paste(0.0, orig.mEnvelope.get());
diff --git a/src/TrackArtist.cpp b/src/TrackArtist.cpp
index 2c3ee0f68..6838ae735 100644
--- a/src/TrackArtist.cpp
+++ b/src/TrackArtist.cpp
@@ -1926,7 +1926,7 @@ void TrackArtist::DrawClipWaveform(const WaveTrack *track,
 
    if (drawEnvelope) {
       DrawEnvelope(dc, mid, env, zoomMin, zoomMax, dB, dBRange);
-      clip->GetEnvelope()->DrawPoints(dc, rect, zoomInfo, dB, dBRange, zoomMin, zoomMax);
+      clip->GetEnvelope()->DrawPoints(dc, rect, zoomInfo, dB, dBRange, zoomMin, zoomMax, true);
    }
 
    // Draw arrows on the left side if the track extends to the left of the
@@ -3209,7 +3209,7 @@ void TrackArtist::DrawTimeTrack(const TimeTrack *track,
       upper = LINEAR_TO_DB(std::max(1.0e-7, upper)) / mdBrange + 1.0;
    }
    track->GetEnvelope()->DrawPoints(dc, envRect, zoomInfo,
-               track->GetDisplayLog(), mdBrange, lower, upper);
+               track->GetDisplayLog(), mdBrange, lower, upper, false);
 }
 
 void TrackArtist::UpdatePrefs()
diff --git a/src/TrackPanel.cpp b/src/TrackPanel.cpp
index 1b8fd67df..66bace059 100644
--- a/src/TrackPanel.cpp
+++ b/src/TrackPanel.cpp
@@ -3213,8 +3213,13 @@ void TrackPanel::ForwardEventToTimeTrackEnvelope(wxMouseEvent & event)
       lower = LINEAR_TO_DB(std::max(1.0e-7, lower)) / dBRange + 1.0;
       upper = LINEAR_TO_DB(std::max(1.0e-7, upper)) / dBRange + 1.0;
    }
+   if (event.ButtonDown()) {
+      mEnvelopeEditor = std::make_unique<EnvelopeEditor>(*pspeedenvelope, false);
+      mEnvelopeEditorRight.reset();
+   }
    bool needUpdate =
-      pspeedenvelope->MouseEvent(
+      mEnvelopeEditor &&
+      mEnvelopeEditor->MouseEvent(
          event, envRect,
          *mViewInfo,
          ptimetrack->GetDisplayLog(), dBRange, lower, upper);
@@ -3250,7 +3255,13 @@ void TrackPanel::ForwardEventToWaveTrackEnvelope(wxMouseEvent & event)
       wxRect envRect = mCapturedRect;
       float zoomMin, zoomMax;
       pwavetrack->GetDisplayBounds(&zoomMin, &zoomMax);
-      needUpdate = penvelope->MouseEvent(
+      if (event.ButtonDown()) {
+         mEnvelopeEditor = std::make_unique<EnvelopeEditor>(*penvelope, true);
+         mEnvelopeEditorRight.reset();
+      }
+      needUpdate =
+         mEnvelopeEditor &&
+         mEnvelopeEditor->MouseEvent(
          event, envRect,
          *mViewInfo,
          dB, dBRange, zoomMin, zoomMax);
@@ -3260,30 +3271,23 @@ void TrackPanel::ForwardEventToWaveTrackEnvelope(wxMouseEvent & event)
       // Assume linked track is wave or null
       const auto link = static_cast<WaveTrack *>(mCapturedTrack->GetLink());
       if (link) {
-         Envelope *e2 = link->GetEnvelopeAtX(event.GetX());
-         // There isn't necessarily an envelope there; no guarantee a
-         // linked track has the same WaveClip structure...
-         bool updateNeeded = false;
-         if (e2) {
+         if (event.ButtonDown()) {
+            Envelope *e2 = link->GetEnvelopeAtX(event.GetX());
+            if (e2)
+               mEnvelopeEditorRight = std::make_unique<EnvelopeEditor>(*e2, true);
+            else {
+               // There isn't necessarily an envelope there; no guarantee a
+               // linked track has the same WaveClip structure...
+            }
+         }
+         if (mEnvelopeEditorRight) {
             wxRect envRect = mCapturedRect;
             float zoomMin, zoomMax;
             pwavetrack->GetDisplayBounds(&zoomMin, &zoomMax);
-            updateNeeded = e2->MouseEvent(event, envRect,
-                                          *mViewInfo, dB, dBRange,
-                                          zoomMin, zoomMax);
-            needUpdate |= updateNeeded;
-         }
-         if(!e2 || !updateNeeded)   // no envelope found at this x point, or found but not updated
-         {
-            if( (e2 = link->GetActiveEnvelope()) != 0 )  // search for any active DragPoint
-            {
-               wxRect envRect = mCapturedRect;
-               float zoomMin, zoomMax;
-               pwavetrack->GetDisplayBounds(&zoomMin, &zoomMax);
-               needUpdate |= e2->MouseEvent(event, envRect,
-                                            *mViewInfo, dB, dBRange,
-                                            zoomMin, zoomMax);
-            }
+            needUpdate|= mEnvelopeEditorRight->MouseEvent(event, envRect,
+                                         *mViewInfo,
+                                         dB, dBRange,
+                                         zoomMin, zoomMax);
          }
       }
 
diff --git a/src/TrackPanel.h b/src/TrackPanel.h
index 6adc12be8..76af1ecc1 100644
--- a/src/TrackPanel.h
+++ b/src/TrackPanel.h
@@ -30,6 +30,7 @@
 class wxMenu;
 class wxRect;
 
+class EnvelopeEditor;
 class LabelTrack;
 class SpectrumAnalyst;
 class TrackPanel;
@@ -809,6 +810,9 @@ protected:
    // Keeps track of extra fractional vertical scroll steps
    double mVertScrollRemainder;
 
+   std::unique_ptr<EnvelopeEditor> mEnvelopeEditor;
+   std::unique_ptr<EnvelopeEditor> mEnvelopeEditorRight;
+
  protected:
 
    // The screenshot class needs to access internals
diff --git a/src/WaveTrack.cpp b/src/WaveTrack.cpp
index 174d612ce..87018fee4 100644
--- a/src/WaveTrack.cpp
+++ b/src/WaveTrack.cpp
@@ -2228,18 +2228,6 @@ Envelope* WaveTrack::GetEnvelopeAtX(int xcoord)
       return NULL;
 }
 
-// Search for any active DragPoint on the current track
-Envelope* WaveTrack::GetActiveEnvelope(void)
-{
-   for (const auto &clip : mClips)
-   {
-      Envelope* env = clip->GetEnvelope() ;
-      if (env->GetDragPoint() >= 0)
-         return env;
-   }
-   return NULL;
-}
-
 Sequence* WaveTrack::GetSequenceAtX(int xcoord)
 {
    WaveClip* clip = GetClipAtX(xcoord);
diff --git a/src/WaveTrack.h b/src/WaveTrack.h
index 4d729da84..372169b6a 100644
--- a/src/WaveTrack.h
+++ b/src/WaveTrack.h
@@ -264,7 +264,6 @@ class AUDACITY_DLL_API WaveTrack final : public Track {
    WaveClip* GetClipAtX(int xcoord);
    Sequence* GetSequenceAtX(int xcoord);
    Envelope* GetEnvelopeAtX(int xcoord);
-   Envelope* GetActiveEnvelope(void);
 
    WaveClip* GetClipAtSample(sampleCount sample);
 
diff --git a/src/effects/Equalization.cpp b/src/effects/Equalization.cpp
index 0138d36ba..9cd91036c 100644
--- a/src/effects/Equalization.cpp
+++ b/src/effects/Equalization.cpp
@@ -241,12 +241,10 @@ EffectEqualization::EffectEqualization()
 
    mLogEnvelope = std::make_unique<Envelope>();
    mLogEnvelope->SetInterpolateDB(false);
-   mLogEnvelope->Mirror(false);
    mLogEnvelope->SetRange(MIN_dBMin, MAX_dBMax); // MB: this is the highest possible range
 
    mLinEnvelope = std::make_unique<Envelope>();
    mLinEnvelope->SetInterpolateDB(false);
-   mLinEnvelope->Mirror(false);
    mLinEnvelope->SetRange(MIN_dBMin, MAX_dBMax); // MB: this is the highest possible range
 
    mEnvelope = (mLin ? mLinEnvelope : mLogEnvelope).get();
@@ -2365,7 +2363,6 @@ void EffectEqualization::ErrMin(void)
    int j=0;
    Envelope testEnvelope;
    testEnvelope.SetInterpolateDB(false);
-   testEnvelope.Mirror(false);
    testEnvelope.SetRange(-120.0, 60.0);
    testEnvelope.Flatten(0.);
    testEnvelope.SetTrackLen(1.0);
@@ -2893,8 +2890,8 @@ EqualizationPanel::EqualizationPanel(EffectEqualization *effect, wxWindow *paren
    mWidth = 0;
    mHeight = 0;
 
+   mEditor = std::make_unique<EnvelopeEditor>(*mEffect->mEnvelope, false);
    mEffect->mEnvelope->Flatten(0.);
-   mEffect->mEnvelope->Mirror(false);
    mEffect->mEnvelope->SetTrackLen(1.0);
 
    ForceRecalc();
@@ -3103,7 +3100,7 @@ void EqualizationPanel::OnPaint(wxPaintEvent &  WXUNUSED(event))
    if( mEffect->mDraw->GetValue() )
    {
       mEffect->mEnvelope->DrawPoints(memDC, mEnvRect, ZoomInfo(0.0, mEnvRect.width-1), false, 0.0,
-                                     mEffect->mdBMin, mEffect->mdBMax);
+                                     mEffect->mdBMin, mEffect->mdBMax, false);
    }
 
    dc.Blit(0, 0, mWidth, mHeight, &memDC, 0, 0, wxCOPY, FALSE);
@@ -3121,7 +3118,7 @@ void EqualizationPanel::OnMouseEvent(wxMouseEvent & event)
       CaptureMouse();
    }
 
-   if (mEffect->mEnvelope->MouseEvent(event, mEnvRect, ZoomInfo(0.0, mEnvRect.width),
+   if (mEditor->MouseEvent(event, mEnvRect, ZoomInfo(0.0, mEnvRect.width),
       false, 0.0,
       mEffect->mdBMin, mEffect->mdBMax))
    {
diff --git a/src/effects/Equalization.h b/src/effects/Equalization.h
index 8923ad9b1..9be3d2da4 100644
--- a/src/effects/Equalization.h
+++ b/src/effects/Equalization.h
@@ -46,6 +46,7 @@
 
 
 class Envelope;
+class EnvelopeEditor;
 class EqualizationPanel;
 
 //
@@ -308,6 +309,7 @@ public:
 private:
    wxWindow *mParent;
    EffectEqualization *mEffect;
+   std::unique_ptr<EnvelopeEditor> mEditor;
 
    bool mRecalcRequired;
 
diff --git a/src/effects/NoiseRemoval.cpp b/src/effects/NoiseRemoval.cpp
index 99f1bd88b..effefc33c 100644
--- a/src/effects/NoiseRemoval.cpp
+++ b/src/effects/NoiseRemoval.cpp
@@ -45,7 +45,6 @@
 
 #include "NoiseRemoval.h"
 
-#include "../Envelope.h"
 #include "../WaveTrack.h"
 #include "../Prefs.h"
 #include "../Project.h"
@@ -883,4 +882,4 @@ void NoiseRemovalDialog::OnTimeSlider(wxCommandEvent & WXUNUSED(event))
    mTimeT->SetValue(wxString::Format(wxT("%.2f"), mTime));
 }
 
-#endif
\ No newline at end of file
+#endif