diff --git a/libraries/lib-builtin-effects/AutoDuckBase.cpp b/libraries/lib-builtin-effects/AutoDuckBase.cpp
index 138416bed..2fcd0e485 100644
--- a/libraries/lib-builtin-effects/AutoDuckBase.cpp
+++ b/libraries/lib-builtin-effects/AutoDuckBase.cpp
@@ -379,7 +379,7 @@ bool AutoDuckBase::ApplyDuckFade(
          buf[(i - pos).as_size_t()] *= DB_TO_LINEAR(gain);
       }
 
-      if (!track.SetFloats(buf.get(), pos, len))
+      if (!track.SetFloats(buf.get(), pos, len, widestSampleFormat, pos + len >= end))
       {
          cancel = true;
          break;
diff --git a/libraries/lib-builtin-effects/ClickRemovalBase.cpp b/libraries/lib-builtin-effects/ClickRemovalBase.cpp
index 8a78314f5..9c91742c1 100644
--- a/libraries/lib-builtin-effects/ClickRemovalBase.cpp
+++ b/libraries/lib-builtin-effects/ClickRemovalBase.cpp
@@ -167,7 +167,7 @@ bool ClickRemovalBase::ProcessOne(
       if (mbDidSomething)
       {
          // RemoveClicks() actually did something.
-         if (!track.SetFloats(buffer.get(), start + s, block))
+         if (!track.SetFloats(buffer.get(), start + s, block, widestSampleFormat, (len - (s + block)) <= windowSize / 2))
          {
             bResult = false;
             break;
diff --git a/libraries/lib-builtin-effects/NormalizeBase.cpp b/libraries/lib-builtin-effects/NormalizeBase.cpp
index 69409716b..21a92d650 100644
--- a/libraries/lib-builtin-effects/NormalizeBase.cpp
+++ b/libraries/lib-builtin-effects/NormalizeBase.cpp
@@ -340,7 +340,7 @@ bool NormalizeBase::ProcessOne(
       ProcessData(buffer.get(), block, offset);
 
       // Copy the newly-changed samples back onto the track.
-      if (!track.SetFloats(buffer.get(), s, block))
+      if (!track.SetFloats(buffer.get(), s, block, widestSampleFormat, s >= end))
       {
          rc = false;
          break;
diff --git a/libraries/lib-builtin-effects/TwoPassSimpleMono.cpp b/libraries/lib-builtin-effects/TwoPassSimpleMono.cpp
index ba5fd985f..a4f0abf34 100644
--- a/libraries/lib-builtin-effects/TwoPassSimpleMono.cpp
+++ b/libraries/lib-builtin-effects/TwoPassSimpleMono.cpp
@@ -176,7 +176,7 @@ bool EffectTwoPassSimpleMono::ProcessOne(WaveChannel &track,
       // onto the track.
       if (mSecondPassDisabled || mPass != 0) {
          if (!outTrack.SetFloats(buffer1.get(), s - samples1,
-            samples1))
+            samples1, widestSampleFormat, s + samples2 >= end))
             return false;
       }
       else
@@ -218,7 +218,7 @@ bool EffectTwoPassSimpleMono::ProcessOne(WaveChannel &track,
    // onto the track.
    if (mSecondPassDisabled || mPass != 0) {
       if (!outTrack.SetFloats(buffer1.get(), s - samples1,
-         samples1))
+         samples1, widestSampleFormat, s >= end))
          return false;
    }
    else
diff --git a/libraries/lib-wave-track/Sequence.cpp b/libraries/lib-wave-track/Sequence.cpp
index e23b0c2ab..0b86926ae 100644
--- a/libraries/lib-wave-track/Sequence.cpp
+++ b/libraries/lib-wave-track/Sequence.cpp
@@ -458,7 +458,9 @@ std::unique_ptr<Sequence> Sequence::Copy( const SampleBlockFactoryPtr &pFactory,
          // Increase ref count or duplicate file
    }
 
+#if defined(_DEBUG)
    dest->ConsistencyCheck(wxT("Sequence::Copy()"));
+#endif
 
    return dest;
 }
@@ -600,7 +602,9 @@ void Sequence::Paste(sampleCount s, const Sequence *src)
 
       // This consistency check won't throw, it asserts.
       // Proof that we kept consistency is not hard.
-      ConsistencyCheck(wxT("Paste branch two"), false);
+#if defined(_DEBUG)
+      ConsistencyCheck(wxT("Paste branch two"));
+#endif
       mSampleFormats.UpdateEffective(src->mSampleFormats.Effective());
       return;
    }
@@ -1635,9 +1639,11 @@ void Sequence::Delete(sampleCount start, sampleCount len)
 
       mNumSamples -= len;
 
+#if defined(_DEBUG)
       // This consistency check won't throw, it asserts.
       // Proof that we kept consistency is not hard.
-      ConsistencyCheck(wxT("Delete - branch one"), false);
+      ConsistencyCheck(wxT("Delete - branch one"));
+#endif
       return;
    }
 
@@ -1745,15 +1751,15 @@ void Sequence::Delete(sampleCount start, sampleCount len)
       (newBlock, mNumSamples - len, wxT("Delete - branch two"));
 }
 
-void Sequence::ConsistencyCheck(const wxChar *whereStr, bool mayThrow) const
+#if defined(_DEBUG)
+void Sequence::ConsistencyCheck(const wxChar *whereStr) const
 {
-   ConsistencyCheck(mBlock, mMaxSamples, 0, mNumSamples, whereStr, mayThrow);
+   ConsistencyCheck(mBlock, mMaxSamples, 0, mNumSamples, whereStr);
 }
 
 void Sequence::ConsistencyCheck
    (const BlockArray &mBlock, size_t maxSamples, size_t from,
-    sampleCount mNumSamples, const wxChar *whereStr,
-    bool WXUNUSED(mayThrow))
+    sampleCount mNumSamples, const wxChar *whereStr)
 {
    // Construction of the exception at the appropriate line of the function
    // gives a little more discrimination
@@ -1794,17 +1800,17 @@ void Sequence::ConsistencyCheck
                  wxT("Recommended course of action:\n")
                  wxT("Undo the failed operation(s), then export or save your work and quit."));
 
-      //if (mayThrow)
-         //throw *ex;
-      //else
-         wxASSERT(false);
+      wxASSERT(false);
    }
 }
+#endif
 
 void Sequence::CommitChangesIfConsistent
    (BlockArray &newBlock, sampleCount numSamples, const wxChar *whereStr)
 {
+#if defined(_DEBUG)
    ConsistencyCheck( newBlock, mMaxSamples, 0, numSamples, whereStr ); // may throw
+#endif
 
    // now commit
    // use No-fail-guarantee
@@ -1848,9 +1854,11 @@ void Sequence::AppendBlocksIfConsistent
    std::copy( additionalBlocks.begin(), additionalBlocks.end(),
               std::back_inserter( mBlock ) );
 
+#if defined(_DEBUG)
    // Check consistency only of the blocks that were added,
    // avoiding quadratic time for repeated checking of repeating appends
    ConsistencyCheck( mBlock, mMaxSamples, prevSize, numSamples, whereStr ); // may throw
+#endif
 
    // now commit
    // use No-fail-guarantee
diff --git a/libraries/lib-wave-track/Sequence.h b/libraries/lib-wave-track/Sequence.h
index f5239f804..2ceeb9c2c 100644
--- a/libraries/lib-wave-track/Sequence.h
+++ b/libraries/lib-wave-track/Sequence.h
@@ -308,10 +308,12 @@ class WAVE_TRACK_API Sequence final : public XMLTagHandler{
    static bool Read(samplePtr buffer, sampleFormat format,
              const SeqBlock &b,
              size_t blockRelativeStart, size_t len, bool mayThrow);
-
+   
+#if defined(_DEBUG)
    // This function throws if the track is messed up
    // because of inconsistent block starts & lengths
-   void ConsistencyCheck (const wxChar *whereStr, bool mayThrow = true) const;
+   void ConsistencyCheck (const wxChar *whereStr) const;
+#endif
 
    // This function prints information to stdout about the blocks in the
    // tracks and indicates if there are inconsistencies.
@@ -319,10 +321,11 @@ class WAVE_TRACK_API Sequence final : public XMLTagHandler{
       (const BlockArray &block, sampleCount numSamples, wxString *dest);
 
 private:
+#if defined(_DEBUG)
    static void ConsistencyCheck
       (const BlockArray &block, size_t maxSamples, size_t from,
-       sampleCount numSamples, const wxChar *whereStr,
-       bool mayThrow = true);
+       sampleCount numSamples, const wxChar *whereStr);
+#endif
 
    // The next two are used in methods that give a strong guarantee.
    // They either throw because final consistency check fails, or swap the
diff --git a/libraries/lib-wave-track/WaveChannelUtilities.h b/libraries/lib-wave-track/WaveChannelUtilities.h
index 39b5ebe98..be24e94b9 100644
--- a/libraries/lib-wave-track/WaveChannelUtilities.h
+++ b/libraries/lib-wave-track/WaveChannelUtilities.h
@@ -163,14 +163,6 @@ WAVE_TRACK_API void SetFloatsFromTime(WaveChannel &channel,
    double t, const float* buffer, size_t numSamples,
    sampleFormat effectiveFormat, PlaybackDirection direction);
 
-/*!
- @copydoc SetFloatsFromTime(WaveChannel &, double, const float *, size_t,
-    sampleFormat, PlaybackDirection)
- */
-WAVE_TRACK_API void SetFloatsFromTime(Clip &channel,
-   double t, const float* buffer, size_t numSamples,
-   sampleFormat effectiveFormat, PlaybackDirection direction);
-
 /*!
  @brief Similar to GetNextClip, but returns `nullptr` if the neighbour
  clip is not adjacent.
diff --git a/libraries/lib-wave-track/WaveClip.cpp b/libraries/lib-wave-track/WaveClip.cpp
index bb9a0926e..fc61f318c 100644
--- a/libraries/lib-wave-track/WaveClip.cpp
+++ b/libraries/lib-wave-track/WaveClip.cpp
@@ -169,10 +169,10 @@ sampleCount WaveClipChannel::GetPlayEndSample() const
 }
 
 void WaveClipChannel::SetSamples(constSamplePtr buffer, sampleFormat format,
-   sampleCount start, size_t len, sampleFormat effectiveFormat)
+   sampleCount start, size_t len, sampleFormat effectiveFormat, bool end)
 {
    return GetClip().SetSamples(miChannel,
-      buffer, format, start, len, effectiveFormat);
+      buffer, format, start, len, effectiveFormat, end);
 }
 
 void WaveClipChannel::WriteXML(XMLWriter &xmlFile) const
@@ -395,7 +395,7 @@ bool WaveClip::GetSamples(samplePtr buffers[], sampleFormat format,
 
 void WaveClip::SetSamples(size_t ii,
    constSamplePtr buffer, sampleFormat format,
-   sampleCount start, size_t len, sampleFormat effectiveFormat)
+   sampleCount start, size_t len, sampleFormat effectiveFormat, bool end)
 {
    assert(ii < NChannels());
    // use Strong-guarantee
@@ -403,7 +403,8 @@ void WaveClip::SetSamples(size_t ii,
       start + TimeToSamples(mTrimLeft), len, effectiveFormat);
 
    // use No-fail-guarantee
-   MarkChanged();
+   if (end)
+      MarkChanged();
 }
 
 void WaveClip::SetEnvelope(std::unique_ptr<Envelope> p)
diff --git a/libraries/lib-wave-track/WaveClip.h b/libraries/lib-wave-track/WaveClip.h
index 28baab286..16cd354a0 100644
--- a/libraries/lib-wave-track/WaveClip.h
+++ b/libraries/lib-wave-track/WaveClip.h
@@ -169,6 +169,7 @@ class WAVE_TRACK_API WaveClipChannel
          If the data are later narrowed from stored format, but not narrower
          than the effective, then no dithering will occur.
       */
+      , bool end = true
    );
 
    void WriteXML(XMLWriter &xmlFile) const;
@@ -553,6 +554,7 @@ class WAVE_TRACK_API WaveClip final :
          If the data are later narrowed from stored format, but not narrower
          than the effective, then no dithering will occur.
       */
+      , bool end = true
    );
 
    //! @}
diff --git a/libraries/lib-wave-track/WaveTrack.cpp b/libraries/lib-wave-track/WaveTrack.cpp
index 943fed3da..236971072 100644
--- a/libraries/lib-wave-track/WaveTrack.cpp
+++ b/libraries/lib-wave-track/WaveTrack.cpp
@@ -1551,7 +1551,7 @@ bool WaveTrack::ReplaceTrackData(
     {
         const auto len = limitSampleBufferSize(GetMaxBlockSize(), end - pos);
         src.DoGet(0, channels, buffersCast, floatSample, seek, len, false);
-        if (!track.SetFloats(buffers, pos, len))
+        if (!track.SetFloats(buffers, pos, len, widestSampleFormat, pos + len >= end))
             retval = false;
         seek += len;
         pos += len;
@@ -2852,7 +2852,7 @@ WaveChannel::GetSampleView(double t0, double t1, bool mayThrow) const
 
 /*! @excsafety{Weak} */
 bool WaveChannel::Set(constSamplePtr buffer, sampleFormat format,
-   sampleCount start, size_t len, sampleFormat effectiveFormat)
+   sampleCount start, size_t len, sampleFormat effectiveFormat, bool end)
 {
    for (const auto &clip: Intervals())
    {
@@ -2889,7 +2889,7 @@ bool WaveChannel::Set(constSamplePtr buffer, sampleFormat format,
 
          clip->SetSamples(
             buffer + startDelta.as_size_t() * SAMPLE_SIZE(format),
-            format, inclipDelta, samplesToCopy.as_size_t(), effectiveFormat );
+            format, inclipDelta, samplesToCopy.as_size_t(), effectiveFormat, end );
       }
    }
    return true;
@@ -3341,14 +3341,14 @@ void WaveTrack::Resample(int rate, BasicUI::ProgressDialog *progress)
 }
 
 bool WaveTrack::SetFloats(const float *const *buffers,
-   sampleCount start, size_t len, sampleFormat effectiveFormat)
+   sampleCount start, size_t len, sampleFormat effectiveFormat, bool end)
 {
    bool result = true;
    size_t ii = 0;
    for (const auto &pChannel : Channels()) {
       const auto buffer = buffers[ii++];
       assert(buffer); // precondition
-      result = pChannel->SetFloats(buffer, start, len, effectiveFormat)
+      result = pChannel->SetFloats(buffer, start, len, effectiveFormat, end)
          && result;
    }
    return result;
diff --git a/libraries/lib-wave-track/WaveTrack.h b/libraries/lib-wave-track/WaveTrack.h
index f43178ded..8b44df933 100644
--- a/libraries/lib-wave-track/WaveTrack.h
+++ b/libraries/lib-wave-track/WaveTrack.h
@@ -156,6 +156,7 @@ class WAVE_TRACK_API WaveChannel final
          If the data are later narrowed from stored format, but not narrower
          than the effective, then no dithering will occur.
       */
+      , bool end = true
    );
 
    //! Random-access assignment of a range of samples
@@ -167,10 +168,11 @@ class WAVE_TRACK_API WaveChannel final
          If the data are later narrowed from stored format, but not narrower
          than the effective, then no dithering will occur.
       */
+      , bool end = true
    )
    {
       return Set(reinterpret_cast<constSamplePtr>(buffer), floatSample,
-         start, len, effectiveFormat);
+         start, len, effectiveFormat, end);
    }
 
    bool AppendBuffer(constSamplePtr buffer, sampleFormat format, size_t len, unsigned stride, sampleFormat effectiveFormat);
@@ -659,6 +661,7 @@ class WAVE_TRACK_API WaveTrack final
          If the data are later narrowed from stored format, but not narrower
          than the effective, then no dithering will occur.
       */
+      , bool end = true
    );
 
    const TypeInfo &GetTypeInfo() const override;
diff --git a/libraries/lib-wave-track/WaveTrackUtilities.cpp b/libraries/lib-wave-track/WaveTrackUtilities.cpp
index 170697f3a..4c22990d6 100644
--- a/libraries/lib-wave-track/WaveTrackUtilities.cpp
+++ b/libraries/lib-wave-track/WaveTrackUtilities.cpp
@@ -101,14 +101,14 @@ bool ReverseOneClip(WaveTrack &track,
       track.GetFloats(0, width, pointers1, second, block);
       reverseBuffers(pointers1, block);
       // Don't dither on later rendering if only reversing samples
+      len -= 2 * block;
       const bool success =
-         track.SetFloats(pointers1, first, block, narrowestSampleFormat)
+         track.SetFloats(pointers1, first, block, narrowestSampleFormat, len <= 1)
          &&
-         track.SetFloats(pointers0, second, block, narrowestSampleFormat);
+         track.SetFloats(pointers0, second, block, narrowestSampleFormat, len <= 1);
       if (!success)
          return false;
 
-      len -= 2 * block;
       first += block;
 
       if (!report(