diff --git a/toonz/sources/image/ffmpeg/tiio_gif.h b/toonz/sources/image/ffmpeg/tiio_gif.h
index fd9bff9..2380b76 100644
--- a/toonz/sources/image/ffmpeg/tiio_gif.h
+++ b/toonz/sources/image/ffmpeg/tiio_gif.h
@@ -21,12 +21,12 @@ public:
   TLevelWriterGif(const TFilePath &path, TPropertyGroup *winfo);
   ~TLevelWriterGif();
   // FfmpegBridge* ffmpeg;
-  void setFrameRate(double fps);
+  void setFrameRate(double fps) override;
 
   TImageWriterP getFrameWriter(TFrameId fid) override;
   void save(const TImageP &image, int frameIndex);
 
-  void saveSoundTrack(TSoundTrack *st);
+  void saveSoundTrack(TSoundTrack *st) override;
 
   static TLevelWriter *create(const TFilePath &path, TPropertyGroup *winfo) {
     return new TLevelWriterGif(path, winfo);
@@ -92,6 +92,6 @@ public:
 // Tiio::Reader *makeGifReader();
 // Tiio::Writer *makeGifWriter();
 
-}  // namespace
+}  // namespace Tiio
 
 #endif
diff --git a/toonz/sources/image/ffmpeg/tiio_mp4.h b/toonz/sources/image/ffmpeg/tiio_mp4.h
index 8748037..d7caae1 100644
--- a/toonz/sources/image/ffmpeg/tiio_mp4.h
+++ b/toonz/sources/image/ffmpeg/tiio_mp4.h
@@ -19,12 +19,12 @@ class TLevelWriterMp4 : public TLevelWriter {
 public:
   TLevelWriterMp4(const TFilePath &path, TPropertyGroup *winfo);
   ~TLevelWriterMp4();
-  void setFrameRate(double fps);
+  void setFrameRate(double fps) override;
 
   TImageWriterP getFrameWriter(TFrameId fid) override;
   void save(const TImageP &image, int frameIndex);
 
-  void saveSoundTrack(TSoundTrack *st);
+  void saveSoundTrack(TSoundTrack *st) override;
 
   static TLevelWriter *create(const TFilePath &path, TPropertyGroup *winfo) {
     return new TLevelWriterMp4(path, winfo);
@@ -88,6 +88,6 @@ public:
 // Tiio::Reader *makeMp4Reader();
 // Tiio::Writer *makeMp4Writer();
 
-}  // namespace
+}  // namespace Tiio
 
 #endif
diff --git a/toonz/sources/image/ffmpeg/tiio_webm.h b/toonz/sources/image/ffmpeg/tiio_webm.h
index 01ff39d..cfee346 100644
--- a/toonz/sources/image/ffmpeg/tiio_webm.h
+++ b/toonz/sources/image/ffmpeg/tiio_webm.h
@@ -18,12 +18,12 @@ class TLevelWriterWebm : public TLevelWriter {
 public:
   TLevelWriterWebm(const TFilePath &path, TPropertyGroup *winfo);
   ~TLevelWriterWebm();
-  void setFrameRate(double fps);
+  void setFrameRate(double fps) override;
 
   TImageWriterP getFrameWriter(TFrameId fid) override;
   void save(const TImageP &image, int frameIndex);
 
-  void saveSoundTrack(TSoundTrack *st);
+  void saveSoundTrack(TSoundTrack *st) override;
 
   static TLevelWriter *create(const TFilePath &path, TPropertyGroup *winfo) {
     return new TLevelWriterWebm(path, winfo);
@@ -87,6 +87,6 @@ public:
 // Tiio::Reader *makeWebmReader();
 // Tiio::Writer *makeWebmWriter();
 
-}  // namespace
+}  // namespace Tiio
 
 #endif
diff --git a/toonz/sources/image/sprite/tiio_sprite.h b/toonz/sources/image/sprite/tiio_sprite.h
index 781141e..ae4d3b1 100644
--- a/toonz/sources/image/sprite/tiio_sprite.h
+++ b/toonz/sources/image/sprite/tiio_sprite.h
@@ -21,12 +21,12 @@ class TLevelWriterSprite : public TLevelWriter {
 public:
   TLevelWriterSprite(const TFilePath &path, TPropertyGroup *winfo);
   ~TLevelWriterSprite();
-  void setFrameRate(double fps);
+  void setFrameRate(double fps) override;
 
   TImageWriterP getFrameWriter(TFrameId fid) override;
   void save(const TImageP &image, int frameIndex);
 
-  void saveSoundTrack(TSoundTrack *st);
+  void saveSoundTrack(TSoundTrack *st) override;
 
   static TLevelWriter *create(const TFilePath &path, TPropertyGroup *winfo) {
     return new TLevelWriterSprite(path, winfo);
@@ -65,6 +65,6 @@ public:
 
 //===========================================================================
 
-}  // namespace
+}  // namespace Tiio
 
 #endif
diff --git a/toonz/sources/include/tools/pinchtool.h b/toonz/sources/include/tools/pinchtool.h
index ff3e657..0b71270 100644
--- a/toonz/sources/include/tools/pinchtool.h
+++ b/toonz/sources/include/tools/pinchtool.h
@@ -63,41 +63,41 @@ public:
   PinchTool();
   virtual ~PinchTool();
 
-  ToolType getToolType() const { return TTool::LevelWriteTool; }
+  ToolType getToolType() const override { return TTool::LevelWriteTool; }
 
   void setShowSelector(bool show) { m_showSelector = show; }
 
-  void onEnter();
-  void onLeave();
+  void onEnter() override;
+  void onLeave() override;
 
-  void updateTranslation();
+  void updateTranslation() override;
 
-  void draw();
+  void draw() override;
 
-  void leftButtonDown(const TPointD &pos, const TMouseEvent &);
+  void leftButtonDown(const TPointD &pos, const TMouseEvent &) override;
 
-  void leftButtonDrag(const TPointD &pos, const TMouseEvent &e);
+  void leftButtonDrag(const TPointD &pos, const TMouseEvent &e) override;
 
-  void leftButtonUp(const TPointD &pos, const TMouseEvent &e);
+  void leftButtonUp(const TPointD &pos, const TMouseEvent &e) override;
 
   void invalidateCursorArea();
 
-  void mouseMove(const TPointD &pos, const TMouseEvent &e);
+  void mouseMove(const TPointD &pos, const TMouseEvent &e) override;
 
   bool moveCursor(const TPointD &pos);
 
   bool keyDown(QKeyEvent *) override;
 
-  void onActivate();
-  void onDeactivate();
+  void onActivate() override;
+  void onDeactivate() override;
 
   // viene usato??
   void update(const TGlobalChange &);
 
-  void onImageChanged();
+  void onImageChanged() override;
 
-  int getCursorId() const { return updateCursor(); }
-  TPropertyGroup *getProperties(int targetType) { return &m_prop; }
+  int getCursorId() const override { return updateCursor(); }
+  TPropertyGroup *getProperties(int targetType) override { return &m_prop; }
 };
 
 #endif  // PINCHTOOL_H
diff --git a/toonz/sources/include/tools/tooloptions.h b/toonz/sources/include/tools/tooloptions.h
index d47a829..aad1d58 100644
--- a/toonz/sources/include/tools/tooloptions.h
+++ b/toonz/sources/include/tools/tooloptions.h
@@ -696,7 +696,7 @@ class ShiftTraceToolOptionBox final : public ToolOptionsBox {
   void resetGhost(int index);
 
 protected:
-  void showEvent(QShowEvent *);
+  void showEvent(QShowEvent *) override;
   void hideEvent(QShowEvent *);
 
 public:
diff --git a/toonz/sources/include/toonz/preferencesitemids.h b/toonz/sources/include/toonz/preferencesitemids.h
index 67ef65b..07dffcd 100644
--- a/toonz/sources/include/toonz/preferencesitemids.h
+++ b/toonz/sources/include/toonz/preferencesitemids.h
@@ -5,16 +5,9 @@ enum PreferencesItemId {
   // General
   defaultViewerEnabled,
   rasterOptimizedMemory,
-  autosaveEnabled,
-  autosavePeriod,
-  autosaveSceneEnabled,
-  autosaveOtherFilesEnabled,
   startupPopupEnabled,
   undoMemorySize,
   taskchunksize,
-  replaceAfterSaveLevelAs,
-  backupEnabled,
-  backupKeepCount,
   sceneNumberingEnabled,
   watchFileSystemEnabled,
   projectRoot,
@@ -66,6 +59,13 @@ enum PreferencesItemId {
 
   //----------
   // Saving
+  autosaveEnabled,
+  autosavePeriod,
+  autosaveSceneEnabled,
+  autosaveOtherFilesEnabled,
+  replaceAfterSaveLevelAs,
+  backupEnabled,
+  backupKeepCount,
   rasterBackgroundColor,
   resetUndoOnSavingLevel,
 
diff --git a/toonz/sources/include/toonzqt/schematicviewer.h b/toonz/sources/include/toonzqt/schematicviewer.h
index 7d86d72..3e5c552 100644
--- a/toonz/sources/include/toonzqt/schematicviewer.h
+++ b/toonz/sources/include/toonzqt/schematicviewer.h
@@ -152,9 +152,9 @@ protected:
   void showEvent(QShowEvent *se) override;
   void enterEvent(QEvent *e) override;
   void leaveEvent(QEvent *e) override;
-  void mouseDoubleClickEvent(QMouseEvent *event);
+  void mouseDoubleClickEvent(QMouseEvent *event) override;
 
-  void tabletEvent(QTabletEvent *e);
+  void tabletEvent(QTabletEvent *e) override;
   void touchEvent(QTouchEvent *e, int type);
   void gestureEvent(QGestureEvent *e);
 
diff --git a/toonz/sources/stdfx/ino_line_blur.cpp b/toonz/sources/stdfx/ino_line_blur.cpp
index f005ae4..9da636a 100644
--- a/toonz/sources/stdfx/ino_line_blur.cpp
+++ b/toonz/sources/stdfx/ino_line_blur.cpp
@@ -6536,7 +6536,8 @@ public:
       bBox = bBox.enlarge(static_cast<double>(margin));
     }
   }
-  bool doGetBBox(double frame, TRectD &bBox, const TRenderSettings &info) {
+  bool doGetBBox(double frame, TRectD &bBox,
+                 const TRenderSettings &info) override {
     if (false == this->m_input.isConnected()) {
       bBox = TRectD();
       return false;
@@ -6546,23 +6547,24 @@ public:
     return ret;
   }
   int getMemoryRequirement(const TRectD &rect, double frame,
-                           const TRenderSettings &info) {
+                           const TRenderSettings &info) override {
     TRectD bBox(rect);
     this->get_render_enlarge(frame, info.m_affine, bBox);
     return TRasterFx::memorySize(bBox, info.m_bpp);
   }
   void transform(double frame, int port, const TRectD &rectOnOutput,
                  const TRenderSettings &infoOnOutput, TRectD &rectOnInput,
-                 TRenderSettings &infoOnInput) {
+                 TRenderSettings &infoOnInput) override {
     rectOnInput = rectOnOutput;
     infoOnInput = infoOnOutput;
     this->get_render_enlarge(frame, infoOnOutput.m_affine, rectOnInput);
   }
-  bool canHandle(const TRenderSettings &info, double frame) {
+  bool canHandle(const TRenderSettings &info, double frame) override {
     // return true;/* geometry処理済の画像に加工することになる */
     return false; /* ここでの処理後にgeometryがかかる */
   }
-  void doCompute(TTile &tile, double frame, const TRenderSettings &rend_sets);
+  void doCompute(TTile &tile, double frame,
+                 const TRenderSettings &rend_sets) override;
 };
 
 FX_PLUGIN_IDENTIFIER(ino_line_blur, "inoLineBlurFx");
diff --git a/toonz/sources/stdfx/iwa_bokehfx.h b/toonz/sources/stdfx/iwa_bokehfx.h
index c0cdf96..8fc309a 100644
--- a/toonz/sources/stdfx/iwa_bokehfx.h
+++ b/toonz/sources/stdfx/iwa_bokehfx.h
@@ -1,4 +1,4 @@
-#pragma once
+#pragma once
 
 /*------------------------------------
 Iwa_BokehFx
@@ -139,11 +139,13 @@ protected:
 public:
   Iwa_BokehFx();
 
-  void doCompute(TTile &tile, double frame, const TRenderSettings &settings);
+  void doCompute(TTile &tile, double frame,
+                 const TRenderSettings &settings) override;
 
-  bool doGetBBox(double frame, TRectD &bBox, const TRenderSettings &info);
+  bool doGetBBox(double frame, TRectD &bBox,
+                 const TRenderSettings &info) override;
 
-  bool canHandle(const TRenderSettings &info, double frame);
+  bool canHandle(const TRenderSettings &info, double frame) override;
 };
 
-#endif
\ No newline at end of file
+#endif
diff --git a/toonz/sources/stdfx/iwa_bokehreffx.h b/toonz/sources/stdfx/iwa_bokehreffx.h
index 4cc453e..0aa8893 100644
--- a/toonz/sources/stdfx/iwa_bokehreffx.h
+++ b/toonz/sources/stdfx/iwa_bokehreffx.h
@@ -1,4 +1,4 @@
-#pragma once
+#pragma once
 
 /*------------------------------------
 Iwa_BokehRefFx
@@ -176,11 +176,13 @@ protected:
 public:
   Iwa_BokehRefFx();
 
-  void doCompute(TTile& tile, double frame, const TRenderSettings& settings);
+  void doCompute(TTile& tile, double frame,
+                 const TRenderSettings& settings) override;
 
-  bool doGetBBox(double frame, TRectD& bBox, const TRenderSettings& info);
+  bool doGetBBox(double frame, TRectD& bBox,
+                 const TRenderSettings& info) override;
 
-  bool canHandle(const TRenderSettings& info, double frame);
+  bool canHandle(const TRenderSettings& info, double frame) override;
 
   void doCompute_CPU(const double frame, const TRenderSettings& settings,
                      float bokehPixelAmount, float maxIrisSize, int margin,
diff --git a/toonz/sources/stdfx/iwa_glarefx.h b/toonz/sources/stdfx/iwa_glarefx.h
index 2ac6419..51b9ddb 100644
--- a/toonz/sources/stdfx/iwa_glarefx.h
+++ b/toonz/sources/stdfx/iwa_glarefx.h
@@ -1,4 +1,4 @@
-#pragma once
+#pragma once
 
 /*------------------------------------
 Iwa_GlareFx
@@ -89,13 +89,15 @@ protected:
 public:
   Iwa_GlareFx();
 
-  void doCompute(TTile &tile, double frame, const TRenderSettings &settings);
+  void doCompute(TTile &tile, double frame,
+                 const TRenderSettings &settings) override;
 
-  bool doGetBBox(double frame, TRectD &bBox, const TRenderSettings &info);
+  bool doGetBBox(double frame, TRectD &bBox,
+                 const TRenderSettings &info) override;
 
-  bool canHandle(const TRenderSettings &info, double frame);
+  bool canHandle(const TRenderSettings &info, double frame) override;
 
   void getParamUIs(TParamUIConcept *&concepts, int &length) override;
 };
 
-#endif
\ No newline at end of file
+#endif
diff --git a/toonz/sources/tnztools/rasterselectiontool.h b/toonz/sources/tnztools/rasterselectiontool.h
index e0f6035..e6f85b0 100644
--- a/toonz/sources/tnztools/rasterselectiontool.h
+++ b/toonz/sources/tnztools/rasterselectiontool.h
@@ -242,7 +242,7 @@ public:
   bool onPropertyChanged(std::string propertyName) override;
   bool getNoAntialiasingValue() { return m_noAntialiasing.getValue(); }
 
-  bool isSelectionEditable() { return m_rasterSelection.isEditable(); }
+  bool isSelectionEditable() override { return m_rasterSelection.isEditable(); }
 
 protected:
   void updateTranslation() override;
diff --git a/toonz/sources/tnztools/rgbpickertool.cpp b/toonz/sources/tnztools/rgbpickertool.cpp
index 6a6e484..261ef4e 100644
--- a/toonz/sources/tnztools/rgbpickertool.cpp
+++ b/toonz/sources/tnztools/rgbpickertool.cpp
@@ -91,6 +91,13 @@ public:
     } else {
       controller->setColorSample(color);
     }
+    TTool::Application *app = TTool::getApplication();
+    TXshSimpleLevel *level  = app->getCurrentLevel()->getSimpleLevel();
+    if (level) {
+      std::vector<TFrameId> fids;
+      level->getFids(fids);
+      invalidateIcons(level, fids);
+    }
   }
 
   void undo() const override { setColor(m_oldValue); }
@@ -236,17 +243,19 @@ void RGBPickerTool::updateTranslation() {
 // another glContext
 
 void RGBPickerTool::onImageChanged() {
+  TTool::Application *app = TTool::getApplication();
+  TXshSimpleLevel *level  = app->getCurrentLevel()->getSimpleLevel();
   if (m_currentStyleId != 0 && m_makePick &&
       (m_pickType.getValue() == POLYLINE_PICK ||
        m_pickType.getValue() == RECT_PICK)) {
-    TTool::Application *app = TTool::getApplication();
-    TPaletteHandle *ph      = app->getPaletteController()->getCurrentPalette();
-    int styleId             = ph->getStyleIndex();
-    TPalette *palette       = ph->getPalette();
-    TXshSimpleLevel *level  = app->getCurrentLevel()->getSimpleLevel();
+    TPaletteHandle *ph = app->getPaletteController()->getCurrentPalette();
+    int styleId        = ph->getStyleIndex();
+    TPalette *palette  = ph->getPalette();
     if (palette)
       TUndoManager::manager()->add(
           new UndoPickRGBM(palette, styleId, m_currentValue, level));
+  }
+  if (m_makePick) {
     setCurrentColor(m_currentValue);
     if (level) {
       std::vector<TFrameId> fids;
@@ -372,7 +381,7 @@ void RGBPickerTool::leftButtonUp(const TPointD &pos, const TMouseEvent &) {
   }
   if (m_pickType.getValue() == FREEHAND_PICK) {
     closeFreehand();
-    if (m_currentStyleId != 0) m_makePick = true;
+    m_makePick = true;
   }
   invalidate();
 }
@@ -460,18 +469,6 @@ void RGBPickerTool::pick() {
   TXshSimpleLevel *level = app->getCurrentLevel()->getSimpleLevel();
   UndoPickRGBM *cmd = new UndoPickRGBM(palette, styleId, m_currentValue, level);
   TUndoManager::manager()->add(cmd);
-  cmd->redo();
-
-  m_makePick = false;
-  /*
-setCurrentColor(m_currentValue);
-if(level)
-{
-vector<TFrameId> fids;
-level->getFids(fids);
-invalidateIcons(level,fids);
-}
-*/
 }
 //---------------------------------------------------------
 
@@ -527,12 +524,6 @@ void RGBPickerTool::pickStroke() {
     TXshSimpleLevel *level = app->getCurrentLevel()->getSimpleLevel();
     TUndoManager::manager()->add(
         new UndoPickRGBM(palette, styleId, m_currentValue, level));
-    setCurrentColor(m_currentValue);
-    if (level) {
-      std::vector<TFrameId> fids;
-      level->getFids(fids);
-      invalidateIcons(level, fids);
-    }
   }
 }
 
@@ -668,7 +659,7 @@ void RGBPickerTool::closePolyline(const TPointD &drawingPos,
 
 //---------------------------------------------------------
 /*! Flipbook上でPassive Pickを有効にする
-*/
+ */
 void RGBPickerTool::showFlipPickedColor(const TPixel32 &pix) {
   if (m_passivePick.getValue()) {
     QColor col((int)pix.r, (int)pix.g, (int)pix.b);
diff --git a/toonz/sources/tnztools/skeletontool.h b/toonz/sources/tnztools/skeletontool.h
index f863a2c..9e8f754 100644
--- a/toonz/sources/tnztools/skeletontool.h
+++ b/toonz/sources/tnztools/skeletontool.h
@@ -35,7 +35,7 @@ public:
       : m_h0(h0), m_h1(h1), m_dist2(dist2) {}
   bool operator<(const MagicLink &link) const { return m_dist2 < link.m_dist2; }
 };
-}
+}  // namespace SkeletonSubtools
 
 class SkeletonTool : public TTool {
   Q_DECLARE_TR_FUNCTIONS(SkeletonTool)
@@ -79,25 +79,25 @@ public:
   SkeletonTool();
   ~SkeletonTool();
 
-  ToolType getToolType() const { return TTool::ColumnTool; }
+  ToolType getToolType() const override { return TTool::ColumnTool; }
 
-  void updateTranslation();  // QString localization stuff
+  void updateTranslation() override;  // QString localization stuff
 
   bool doesApply() const;  // ritorna vero se posso deformare l'oggetto corrente
 
-  void onEnter() {}
-  void leftButtonDown(const TPointD &pos, const TMouseEvent &);
-  void leftButtonDrag(const TPointD &pos, const TMouseEvent &);
-  void leftButtonUp(const TPointD &pos, const TMouseEvent &);
-  void mouseMove(const TPointD &, const TMouseEvent &e);
+  void onEnter() override {}
+  void leftButtonDown(const TPointD &pos, const TMouseEvent &) override;
+  void leftButtonDrag(const TPointD &pos, const TMouseEvent &) override;
+  void leftButtonUp(const TPointD &pos, const TMouseEvent &) override;
+  void mouseMove(const TPointD &, const TMouseEvent &e) override;
 
-  void onImageChanged() { invalidate(); }
+  void onImageChanged() override { invalidate(); }
 
-  void reset() { m_temporaryPinnedColumns.clear(); }
+  void reset() override { m_temporaryPinnedColumns.clear(); }
 
-  bool onPropertyChanged(std::string propertyName);
+  bool onPropertyChanged(std::string propertyName) override;
 
-  void draw();
+  void draw() override;
 
   void drawSkeleton(const Skeleton &skeleton, int row);
   void drawLevelBoundingBox(int frame, int columnIndex);
@@ -122,21 +122,21 @@ public:
 
   bool keyDown(QKeyEvent *event) override;
 
-  void onActivate();
-  void onDeactivate();
+  void onActivate() override;
+  void onDeactivate() override;
 
   int getMagicLinkCount() const { return (int)m_magicLinks.size(); }
   SkeletonSubtools::MagicLink getMagicLink(int index) const;
 
   void magicLink(int index);
 
-  int getCursorId() const;
+  int getCursorId() const override;
 
   // TRaster32P getToolIcon() const {return Pixmaps::arrow;}
-  TPropertyGroup *getProperties(int targetType) { return &m_prop; }
+  TPropertyGroup *getProperties(int targetType) override { return &m_prop; }
 
-  void updateMatrix() { setMatrix(getCurrentObjectParentMatrix()); }
-  void addContextMenuItems(QMenu *menu);
+  void updateMatrix() override { setMatrix(getCurrentObjectParentMatrix()); }
+  void addContextMenuItems(QMenu *menu) override;
   bool select(const TSelection *) { return false; }
 
   void togglePinnedStatus(int columnIndex, int frame, bool shiftPressed);
diff --git a/toonz/sources/tnztools/stylepickertool.h b/toonz/sources/tnztools/stylepickertool.h
index 65a46c7..a838631 100644
--- a/toonz/sources/tnztools/stylepickertool.h
+++ b/toonz/sources/tnztools/stylepickertool.h
@@ -42,7 +42,7 @@ public:
 
   int getCursorId() const override;
 
-  bool onPropertyChanged(std::string propertyName);
+  bool onPropertyChanged(std::string propertyName) override;
 
   bool isOrganizePaletteActive() { return m_organizePalette.getValue(); }
 
@@ -57,4 +57,4 @@ public:
   void updateTranslation() override;
 };
 
-#endif
\ No newline at end of file
+#endif
diff --git a/toonz/sources/tnztools/vectorselectiontool.h b/toonz/sources/tnztools/vectorselectiontool.h
index 94f79e5..ba90050 100644
--- a/toonz/sources/tnztools/vectorselectiontool.h
+++ b/toonz/sources/tnztools/vectorselectiontool.h
@@ -312,7 +312,7 @@ public:
   void setResetCenter(bool update) { m_resetCenter = update; }
   bool canResetCenter() { return m_resetCenter; }
 
-  bool isSelectionEditable() { return m_strokeSelection.isEditable(); }
+  bool isSelectionEditable() override { return m_strokeSelection.isEditable(); }
 
 protected:
   void onActivate() override;
diff --git a/toonz/sources/tnztools/viewtools.h b/toonz/sources/tnztools/viewtools.h
index 786ee67..61b4560 100644
--- a/toonz/sources/tnztools/viewtools.h
+++ b/toonz/sources/tnztools/viewtools.h
@@ -37,7 +37,7 @@ public:
 
   int getCursorId() const override;
 
-  void updateTranslation() {
+  void updateTranslation() override {
     m_cameraCentered.setQStringName(tr("Rotate On Camera Center"));
   }
 };
diff --git a/toonz/sources/toonz/convertpopup.cpp b/toonz/sources/toonz/convertpopup.cpp
index f0e9dad..659843e 100644
--- a/toonz/sources/toonz/convertpopup.cpp
+++ b/toonz/sources/toonz/convertpopup.cpp
@@ -511,6 +511,8 @@ ConvertPopup::ConvertPopup(bool specifyInput)
     ret = ret && connect(m_convertFileFld, SIGNAL(pathChanged()), this,
                          SLOT(onFileInChanged()));
 
+  // resize the dialog
+  onFormatSelected(m_fileFormat->currentText());
   // update unable/enable of checkboxes
   onTlvModeSelected(m_tlvMode->currentText());
 
@@ -762,6 +764,11 @@ void ConvertPopup::onFormatSelected(const QString &format) {
     m_saveBackupToNopaint->setEnabled(m_tlvMode->currentText() ==
                                       TlvMode_Unpainted);
   }
+  // For unknown reasons, calling adjustSize twice is needed to
+  // prevent the dialog from remaining large size when the current
+  // format is switched from tlv to another format.
+  adjustSize();
+  adjustSize();
 }
 
 //------------------------------------------------------------------
diff --git a/toonz/sources/toonz/filebrowserpopup.h b/toonz/sources/toonz/filebrowserpopup.h
index c1ac1c9..0e2289a 100644
--- a/toonz/sources/toonz/filebrowserpopup.h
+++ b/toonz/sources/toonz/filebrowserpopup.h
@@ -218,7 +218,7 @@ protected:
   void showEvent(QShowEvent *) override;
 
 protected slots:
-  void onFilePathDoubleClicked(const TFilePath &path);
+  void onFilePathDoubleClicked(const TFilePath &path) override;
 };
 
 //-----------------------------------------------------------------------------
@@ -313,7 +313,7 @@ protected slots:
   // the selection
   void onSelectionChanged(TSelection *selection);
 
-  void onFilePathDoubleClicked(const TFilePath &path);
+  void onFilePathDoubleClicked(const TFilePath &path) override;
 
   void onPreferenceChanged(const QString &);
 
diff --git a/toonz/sources/toonz/imageviewer.h b/toonz/sources/toonz/imageviewer.h
index 895a963..bec3163 100644
--- a/toonz/sources/toonz/imageviewer.h
+++ b/toonz/sources/toonz/imageviewer.h
@@ -146,10 +146,10 @@ protected:
 
   void dragCompare(const QPoint &dp);
 
-  void tabletEvent(QTabletEvent *e);
+  void tabletEvent(QTabletEvent *e) override;
   void touchEvent(QTouchEvent *e, int type);
   void gestureEvent(QGestureEvent *e);
-  bool event(QEvent *e);
+  bool event(QEvent *e) override;
 
 public slots:
 
diff --git a/toonz/sources/toonz/layerheaderpanel.h b/toonz/sources/toonz/layerheaderpanel.h
index 70adb6f..1f6b49e 100644
--- a/toonz/sources/toonz/layerheaderpanel.h
+++ b/toonz/sources/toonz/layerheaderpanel.h
@@ -46,8 +46,8 @@ protected:
   void mousePressEvent(QMouseEvent *event) override;
   void mouseMoveEvent(QMouseEvent *event) override;
   void mouseReleaseEvent(QMouseEvent *event) override;
-  void enterEvent(QEvent *);
-  void leaveEvent(QEvent *);
+  void enterEvent(QEvent *) override;
+  void leaveEvent(QEvent *) override;
   bool event(QEvent *event) override;
 
 private:
diff --git a/toonz/sources/toonz/levelsettingspopup.cpp b/toonz/sources/toonz/levelsettingspopup.cpp
index f50fb5f..4540711 100644
--- a/toonz/sources/toonz/levelsettingspopup.cpp
+++ b/toonz/sources/toonz/levelsettingspopup.cpp
@@ -612,6 +612,7 @@ void LevelSettingsPopup::onPreferenceChanged(const QString &propertyName) {
   int decimals = (pixelsMode) ? 0 : 4;
   m_widthFld->setDecimals(decimals);
   m_heightFld->setDecimals(decimals);
+  adjustSize();
 }
 
 //-----------------------------------------------------------------------------
diff --git a/toonz/sources/toonz/penciltestpopup.h b/toonz/sources/toonz/penciltestpopup.h
index 389870e..48b65b9 100644
--- a/toonz/sources/toonz/penciltestpopup.h
+++ b/toonz/sources/toonz/penciltestpopup.h
@@ -279,9 +279,9 @@ public:
   ~PencilTestPopup();
 
 protected:
-  void showEvent(QShowEvent* event);
-  void hideEvent(QHideEvent* event);
-  void keyPressEvent(QKeyEvent* event);
+  void showEvent(QShowEvent* event) override;
+  void hideEvent(QHideEvent* event) override;
+  void keyPressEvent(QKeyEvent* event) override;
 
   bool event(QEvent* e) override;
 
@@ -320,4 +320,4 @@ public slots:
   void openSaveInFolderPopup();
 };
 
-#endif
\ No newline at end of file
+#endif
diff --git a/toonz/sources/toonz/preferencespopup.cpp b/toonz/sources/toonz/preferencespopup.cpp
index 1163909..11a9147 100644
--- a/toonz/sources/toonz/preferencespopup.cpp
+++ b/toonz/sources/toonz/preferencespopup.cpp
@@ -51,6 +51,7 @@
 #include <QStringList>
 #include <QListWidget>
 #include <QGroupBox>
+#include <QKeySequence>
 
 using namespace DVGui;
 
@@ -998,6 +999,13 @@ void PreferencesPopup::insertFootNote(QGridLayout* layout) {
 //-----------------------------------------------------------------------------
 
 QString PreferencesPopup::getUIString(PreferencesItemId id) {
+  auto CtrlAltStr = []() {
+    QString str =
+        QKeySequence(Qt::CTRL + Qt::ALT).toString(QKeySequence::NativeText);
+    if (str.endsWith("+")) str.chop(1);
+    return str;
+  };
+
   const static QMap<PreferencesItemId, QString> uiStringTable = {
       // General
       {defaultViewerEnabled, tr("Use Default Viewer for Movie Formats")},
@@ -1040,7 +1048,7 @@ QString PreferencesPopup::getUIString(PreferencesItemId id) {
        tr("Show Raster Images Darken Blended")},
       {showFrameNumberWithLetters,
        tr("Show \"ABC\" Appendix to the Frame Number in Xsheet Cell")},
-      {iconSize, tr("Level Strip Icon Size*:")},
+      {iconSize, tr("Level Strip Thumbnail Size*:")},
       {viewShrink, tr("Viewer Shrink:")},
       {viewStep, tr("Step:")},
       {viewerZoomCenter, tr("Viewer Zoom Center:")},
@@ -1112,7 +1120,7 @@ QString PreferencesPopup::getUIString(PreferencesItemId id) {
       {cursorBrushStyle, tr("Cursor Style:")},
       {cursorOutlineEnabled, tr("Show Cursor Size Outlines")},
       {levelBasedToolsDisplay, tr("Toolbar Display Behaviour:")},
-      {useCtrlAltToResizeBrush, tr("Use Ctrl+Alt to Resize Brush")},
+      {useCtrlAltToResizeBrush, tr("Use %1 to Resize Brush").arg(CtrlAltStr())},
 
       // Xsheet
       {xsheetLayoutPreference, tr("Column Header Layout*:")},
@@ -1372,18 +1380,9 @@ QWidget* PreferencesPopup::createGeneralPage() {
 
   insertUI(defaultViewerEnabled, lay);
   insertUI(rasterOptimizedMemory, lay);
-  QGridLayout* autoSaveLay = insertGroupBoxUI(autosaveEnabled, lay);
-  {
-    insertUI(autosavePeriod, autoSaveLay);
-    insertUI(autosaveSceneEnabled, autoSaveLay);
-    insertUI(autosaveOtherFilesEnabled, autoSaveLay);
-  }
   insertUI(startupPopupEnabled, lay);
   insertUI(undoMemorySize, lay);
   insertUI(taskchunksize, lay);
-  insertUI(replaceAfterSaveLevelAs, lay);
-  QGridLayout* backupLay = insertGroupBoxUI(backupEnabled, lay);
-  { insertUI(backupKeepCount, backupLay); }
   insertUI(sceneNumberingEnabled, lay);
   insertUI(watchFileSystemEnabled, lay);
 
@@ -1621,13 +1620,21 @@ QWidget* PreferencesPopup::createSavingPage() {
   QWidget* widget  = new QWidget(this);
   QGridLayout* lay = new QGridLayout();
   setupLayout(lay);
-
+  QGridLayout* autoSaveLay = insertGroupBoxUI(autosaveEnabled, lay);
+  {
+    insertUI(autosavePeriod, autoSaveLay);
+    insertUI(autosaveSceneEnabled, autoSaveLay);
+    insertUI(autosaveOtherFilesEnabled, autoSaveLay);
+  }
+  insertUI(replaceAfterSaveLevelAs, lay);
+  QGridLayout* backupLay = insertGroupBoxUI(backupEnabled, lay);
+  { insertUI(backupKeepCount, backupLay); }
   QLabel* matteColorLabel =
       new QLabel(tr("Matte color is used for background when overwriting "
                     "raster levels with transparent pixels\nin non "
                     "alpha-enabled image format."),
                  this);
-  lay->addWidget(matteColorLabel, 0, 0, 1, 3, Qt::AlignLeft);
+  lay->addWidget(matteColorLabel, lay->rowCount(), 0, 1, 3, Qt::AlignLeft);
   insertUI(rasterBackgroundColor, lay);
   insertUI(resetUndoOnSavingLevel, lay);
 
diff --git a/toonz/sources/toonz/sceneviewer.h b/toonz/sources/toonz/sceneviewer.h
index d200041..6b6311b 100644
--- a/toonz/sources/toonz/sceneviewer.h
+++ b/toonz/sources/toonz/sceneviewer.h
@@ -259,8 +259,8 @@ public:
   bool canSwapCompared() const;
 
   bool isEditPreviewSubcamera() const { return m_editPreviewSubCamera; }
-  bool getIsFlippedX() const { return m_isFlippedX; }
-  bool getIsFlippedY() const { return m_isFlippedY; }
+  bool getIsFlippedX() const override { return m_isFlippedX; }
+  bool getIsFlippedY() const override { return m_isFlippedY; }
   void setEditPreviewSubcamera(bool enabled) {
     m_editPreviewSubCamera = enabled;
   }
@@ -281,10 +281,10 @@ public:
 
   void setIsLocator() { m_isLocator = true; }
   void setIsStyleShortcutSwitchable() { m_isStyleShortcutSwitchable = true; }
-  int getVGuideCount();
-  int getHGuideCount();
-  double getVGuide(int index);
-  double getHGuide(int index);
+  int getVGuideCount() override;
+  int getHGuideCount() override;
+  double getVGuide(int index) override;
+  double getHGuide(int index) override;
 
   void bindFBO() override;
   void releaseFBO() override;
diff --git a/toonz/sources/toonz/subscenecommand.cpp b/toonz/sources/toonz/subscenecommand.cpp
index 9876bd7..df6e55b 100644
--- a/toonz/sources/toonz/subscenecommand.cpp
+++ b/toonz/sources/toonz/subscenecommand.cpp
@@ -488,10 +488,6 @@ TFx *explodeFxSubTree(TFx *innerFx, QMap<TFx *, QPair<TFx *, int>> &fxs,
   } else {
     TFxSet *innerTerminals = innerDag->getTerminalFxs();
     int i, terminalCount = innerTerminals->getFxCount();
-    if (!terminalCount) {
-      fxs[innerFx] = QPair<TFx *, int>(nullptr, -1);
-      return nullptr;
-    }
     QMultiMap<int, TFx *> sortedFx;
     for (i = 0; i < terminalCount; i++) {
       TFx *terminalFx = innerTerminals->getFx(i);
@@ -508,6 +504,13 @@ TFx *explodeFxSubTree(TFx *innerFx, QMap<TFx *, QPair<TFx *, int>> &fxs,
         return nullptr;
     }
 
+    // in case no nodes connected to the xsheet the xsheet node will not be
+    // merged, but will just be removed
+    if (terminalCount == 0) {
+      fxs[innerFx] = QPair<TFx *, int>(nullptr, -1);
+      return innerFx;  // just to return non-zero value
+    }
+
     TFx *root = sortedFx.begin().value();
 
     // If only one node is connected to the Xsheet node, then skip bringing it
@@ -836,7 +839,7 @@ void explodeFxs(TXsheet *xsh, TXsheet *subXsh, const GroupData &fxGroupData,
                                innerDag, fxGroupData, outPorts);
 
   // in case the child and parent Xsheet nodes will be "merged"
-  if (!root && innerDag->getTerminalFxs()->getFxCount()) {
+  if (!root) {
     TFxSet *internals = innerDag->getTerminalFxs();
     for (int j = 0; j < internals->getFxCount(); j++) {
       TFx *fx = internals->getFx(j);
@@ -914,6 +917,7 @@ void explodeFxs(TXsheet *xsh, TXsheet *subXsh, const GroupData &fxGroupData,
     TFx *outerFx           = pair.first;
     // skip redundant item. in case when only one node is input to the xsheet
     // node in the inner dag
+    if (!outerFx) continue;
     if (outerFx->getAttributes()->getGroupId() == groupId) continue;
     outerFx->getAttributes()->setGroupId(groupId);
     outerFx->getAttributes()->setGroupName(L"Group " +
@@ -972,6 +976,7 @@ std::set<int> explode(TXsheet *xsh, TXsheet *subXsh, int index,
 
   QMap<TFx *, TFx *> fxMap;
   for (auto it = fxs.constBegin(); it != fxs.constEnd(); ++it) {
+    if (it.value().first == nullptr) continue;
     setGrammerToParams(it.value().first->getParams(), grammer);
     fxMap.insert(it.key(), it.value().first);
   }
diff --git a/toonz/sources/toonzlib/imagebuilders.h b/toonz/sources/toonzlib/imagebuilders.h
index 6a437a0..5284666 100644
--- a/toonz/sources/toonzlib/imagebuilders.h
+++ b/toonz/sources/toonzlib/imagebuilders.h
@@ -60,8 +60,8 @@ public:
                                   bool cacheImagesAsWell) override;
 
   /* Exposed to allow Fid to be updated due to a renumber operation
-  */
-  void setFid(const TFrameId &fid);
+   */
+  void setFid(const TFrameId &fid) override;
 
 protected:
   bool getInfo(TImageInfo &info, int imFlags, void *extData) override;
diff --git a/toonz/sources/toonzlib/preferences.cpp b/toonz/sources/toonzlib/preferences.cpp
index 143314c..65d711c 100644
--- a/toonz/sources/toonzlib/preferences.cpp
+++ b/toonz/sources/toonzlib/preferences.cpp
@@ -337,19 +337,9 @@ void Preferences::definePreferenceItems() {
   define(defaultViewerEnabled, "defaultViewerEnabled", QMetaType::Bool, false);
   define(rasterOptimizedMemory, "rasterOptimizedMemory", QMetaType::Bool,
          false);
-  define(autosaveEnabled, "autosaveEnabled", QMetaType::Bool, false);
-  define(autosavePeriod, "autosavePeriod", QMetaType::Int, 15, 1, 60);
-  define(autosaveSceneEnabled, "autosaveSceneEnabled", QMetaType::Bool, true);
-  define(autosaveOtherFilesEnabled, "autosaveOtherFilesEnabled",
-         QMetaType::Bool, true);
   define(startupPopupEnabled, "startupPopupEnabled", QMetaType::Bool, true);
   define(undoMemorySize, "undoMemorySize", QMetaType::Int, 100, 0, 2000);
   define(taskchunksize, "taskchunksize", QMetaType::Int, 10, 1, 2000);
-  define(replaceAfterSaveLevelAs, "replaceAfterSaveLevelAs", QMetaType::Bool,
-         true);
-  define(backupEnabled, "backupEnabled", QMetaType::Bool, true);
-  define(backupKeepCount, "backupKeepCount", QMetaType::Int, 1, 1,
-         std::numeric_limits<int>::max());
   define(sceneNumberingEnabled, "sceneNumberingEnabled", QMetaType::Bool,
          false);
   define(watchFileSystemEnabled, "watchFileSystemEnabled", QMetaType::Bool,
@@ -359,8 +349,6 @@ void Preferences::definePreferenceItems() {
   define(pathAliasPriority, "pathAliasPriority", QMetaType::Int,
          (int)ProjectFolderOnly);
 
-  setCallBack(autosaveEnabled, &Preferences::enableAutosave);
-  setCallBack(autosavePeriod, &Preferences::setAutosavePeriod);
   setCallBack(undoMemorySize, &Preferences::setUndoMemorySize);
 
   // Interface
@@ -431,12 +419,24 @@ void Preferences::definePreferenceItems() {
   //"levelFormats" need to be handle separately
 
   // Saving
+  define(autosaveEnabled, "autosaveEnabled", QMetaType::Bool, false);
+  define(autosavePeriod, "autosavePeriod", QMetaType::Int, 15, 1, 60);
+  define(autosaveSceneEnabled, "autosaveSceneEnabled", QMetaType::Bool, true);
+  define(autosaveOtherFilesEnabled, "autosaveOtherFilesEnabled",
+         QMetaType::Bool, true);
+  define(replaceAfterSaveLevelAs, "replaceAfterSaveLevelAs", QMetaType::Bool,
+         true);
+  define(backupEnabled, "backupEnabled", QMetaType::Bool, true);
+  define(backupKeepCount, "backupKeepCount", QMetaType::Int, 1, 1,
+         std::numeric_limits<int>::max());
   define(rasterBackgroundColor, "rasterBackgroundColor", QMetaType::QColor,
          QColor(Qt::white));
   define(resetUndoOnSavingLevel, "resetUndoOnSavingLevel", QMetaType::Bool,
          true);
 
   setCallBack(rasterBackgroundColor, &Preferences::setRasterBackgroundColor);
+  setCallBack(autosaveEnabled, &Preferences::enableAutosave);
+  setCallBack(autosavePeriod, &Preferences::setAutosavePeriod);
 
   // Import / Export
   define(ffmpegPath, "ffmpegPath", QMetaType::QString, "");
diff --git a/toonz/sources/toonzlib/tpalettehandle.cpp b/toonz/sources/toonzlib/tpalettehandle.cpp
index 0013507..1fbaa56 100644
--- a/toonz/sources/toonzlib/tpalettehandle.cpp
+++ b/toonz/sources/toonzlib/tpalettehandle.cpp
@@ -32,7 +32,7 @@ public:
 
   void redo() const override { toggleAutopaint(); }
 
-  void onAdd() { redo(); }
+  void onAdd() override { redo(); }
 
   int getSize() const override { return sizeof(*this); }
 
@@ -212,4 +212,4 @@ void TPaletteHandle::toggleAutopaint() {
   if (index > 0) {
     TUndoManager::manager()->add(new AutopaintToggleUndo(this, index));
   }
-}
\ No newline at end of file
+}
diff --git a/toonz/sources/toonzqt/colorfield.cpp b/toonz/sources/toonzqt/colorfield.cpp
index c37e04e..236366b 100644
--- a/toonz/sources/toonzqt/colorfield.cpp
+++ b/toonz/sources/toonzqt/colorfield.cpp
@@ -197,7 +197,7 @@ ChannelField::ChannelField(QWidget *parent, const QString &string, int value,
   QLabel *channelName = new QLabel(string, this);
   m_channelEdit       = new DVGui::IntLineEdit(this, value, 0, maxValue);
   m_channelSlider     = new QSlider(Qt::Horizontal, this);
-
+  m_channelSlider->setFocusPolicy(Qt::NoFocus);
   channelName->setAlignment(Qt::AlignRight | Qt::AlignVCenter);
   channelName->setFixedWidth(labelWidth);
 
diff --git a/toonz/sources/toonzqt/functionsegmentviewer.cpp b/toonz/sources/toonzqt/functionsegmentviewer.cpp
index ca1d3dc..c4cc812 100644
--- a/toonz/sources/toonzqt/functionsegmentviewer.cpp
+++ b/toonz/sources/toonzqt/functionsegmentviewer.cpp
@@ -117,9 +117,9 @@ SpeedInOutSegmentPage::SpeedInOutSegmentPage(FunctionSegmentViewer *parent)
 
   bool ret = connect(m_speed0xFld, SIGNAL(editingFinished()), this,
                      SLOT(onFirstHandleXChanged()));
-  ret = ret && connect(m_speed0yFld, SIGNAL(editingFinished()), this,
+  ret      = ret && connect(m_speed0yFld, SIGNAL(editingFinished()), this,
                        SLOT(onFirstHandleYChanged()));
-  ret = ret && connect(m_firstSpeedFld, SIGNAL(editingFinished()), this,
+  ret      = ret && connect(m_firstSpeedFld, SIGNAL(editingFinished()), this,
                        SLOT(onFirstSpeedChanged()));
 
   ret = ret && connect(m_speed1xFld, SIGNAL(editingFinished()), this,
@@ -557,11 +557,11 @@ void FunctionExpressionSegmentPage::init(int segmentLength) {
 
   /*--- すでにあるカーブをExpressionに切り替えた場合 ---*/
   if (kIndex >= 0) {
-    TDoubleKeyframe keyFrame      = curve->getKeyframe(kIndex);
-    double value                  = curve->getValue(keyFrame.m_frame);
-    const TUnit *unit             = 0;
+    TDoubleKeyframe keyFrame = curve->getKeyframe(kIndex);
+    double value             = curve->getValue(keyFrame.m_frame);
+    const TUnit *unit        = 0;
     if (curve->getMeasure()) unit = curve->getMeasure()->getCurrentUnit();
-    if (unit) value               = unit->convertTo(value);
+    if (unit) value = unit->convertTo(value);
     m_expressionFld->setExpression(QString::number(value).toStdString());
     /*--- unitがある場合だけUnitを表示 ---*/
     if (unit)
@@ -704,20 +704,20 @@ FileSegmentPage::FileSegmentPage(FunctionSegmentViewer *parent)
 void FileSegmentPage::refresh() {
   TDoubleKeyframe kf;
   TDoubleParam *curve = getCurve();
-  if (curve) kf       = curve->getKeyframeAt(getR0());
+  if (curve) kf = curve->getKeyframeAt(getR0());
   if (curve && kf.m_isKeyframe) {
     TFilePath path;
     int fieldIndex       = 0;
     std::string unitName = "";
     if (kf.m_type == TDoubleKeyframe::File) {
-      path                           = kf.m_fileParams.m_path;
-      fieldIndex                     = kf.m_fileParams.m_fieldIndex;
+      path       = kf.m_fileParams.m_path;
+      fieldIndex = kf.m_fileParams.m_fieldIndex;
       if (fieldIndex < 0) fieldIndex = 0;
-      unitName                       = kf.m_unitName;
+      unitName = kf.m_unitName;
       if (unitName == "") {
         TMeasure *measure = curve->getMeasure();
         if (measure) {
-          const TUnit *unit  = measure->getCurrentUnit();
+          const TUnit *unit = measure->getCurrentUnit();
           if (unit) unitName = ::to_string(unit->getDefaultExtension());
         }
       }
@@ -735,7 +735,7 @@ void FileSegmentPage::init(int segmentLength) {
   TMeasure *measure    = curve->getMeasure();
   std::string unitName = "";
   if (measure) {
-    const TUnit *unit  = measure->getCurrentUnit();
+    const TUnit *unit = measure->getCurrentUnit();
     if (unit) unitName = ::to_string(unit->getDefaultExtension());
   }
   m_measureFld->setText(QString::fromStdString(unitName));
@@ -1042,17 +1042,17 @@ FunctionSegmentViewer::FunctionSegmentViewer(QWidget *parent,
   bool ret = true;
   ret      = ret && connect(m_typeCombo, SIGNAL(currentIndexChanged(int)),
                        m_parametersPanel, SLOT(setCurrentIndex(int)));
-  ret = ret && connect(m_typeCombo, SIGNAL(activated(int)), this,
+  ret      = ret && connect(m_typeCombo, SIGNAL(activated(int)), this,
                        SLOT(onSegmentTypeChanged(int)));
-  ret = ret && connect(applyButton, SIGNAL(clicked()), this,
+  ret      = ret && connect(applyButton, SIGNAL(clicked()), this,
                        SLOT(onApplyButtonPressed()));
-  ret = ret && connect(m_prevCurveButton, SIGNAL(clicked()), this,
+  ret      = ret && connect(m_prevCurveButton, SIGNAL(clicked()), this,
                        SLOT(onPrevCurveButtonPressed()));
-  ret = ret && connect(m_nextCurveButton, SIGNAL(clicked()), this,
+  ret      = ret && connect(m_nextCurveButton, SIGNAL(clicked()), this,
                        SLOT(onNextCurveButtonPressed()));
-  ret = ret && connect(m_prevLinkButton, SIGNAL(clicked()), this,
+  ret      = ret && connect(m_prevLinkButton, SIGNAL(clicked()), this,
                        SLOT(onPrevLinkButtonPressed()));
-  ret = ret && connect(m_nextLinkButton, SIGNAL(clicked()), this,
+  ret      = ret && connect(m_nextLinkButton, SIGNAL(clicked()), this,
                        SLOT(onNextLinkButtonPressed()));
   assert(ret);
 
@@ -1104,7 +1104,7 @@ void FunctionSegmentViewer::setSegmentByFrame(TDoubleParam *curve, int frame) {
       if (k1 >= 1)
         segmentIndex = k1 - 1;
       else {
-        int k0                    = m_curve->getPrevKeyframe(frame);
+        int k0 = m_curve->getPrevKeyframe(frame);
         if (k0 >= 0) segmentIndex = k0;
       }
     } else {
@@ -1276,9 +1276,9 @@ void FunctionSegmentViewer::onCurveChanged() {
 
 void FunctionSegmentViewer::onStepFieldChanged(const QString &text) {
   if (!segmentIsValid()) return;
-  int step             = 1;
+  int step = 1;
   if (text != "") step = text.toInt();
-  if (step < 1) step   = 1;
+  if (step < 1) step = 1;
   KeyframeSetter setter(m_curve, m_segmentIndex);
   setter.setStep(step);
 }
@@ -1383,8 +1383,8 @@ void FunctionSegmentViewer::onApplyButtonPressed() {
   /*--- from -
    * toに合わせてキーフレームを作成しようと試みる。すでに有る場合はスキップ
    * ---*/
-  if (fromFrame < 0) fromFrame        = 0;
-  if (toFrame < 0) toFrame            = 0;
+  if (fromFrame < 0) fromFrame = 0;
+  if (toFrame < 0) toFrame = 0;
   if (fromFrame >= toFrame) fromFrame = toFrame + 1;
 
   if (!m_curve->isKeyframe(fromFrame))
@@ -1469,7 +1469,7 @@ void FunctionSegmentViewer::onPrevCurveButtonPressed() {
 
   int r0 = (int)prevKey.m_frame;
   int r1 = (int)currentKey.m_frame;
-
+  m_panel->update();
   m_sheet->getSelection()->selectSegment(m_curve, currentKeyIndex - 1,
                                          QRect(col, r0, 1, r1 - r0 + 1));
   m_sheet->updateAll();
@@ -1502,7 +1502,7 @@ void FunctionSegmentViewer::onNextCurveButtonPressed() {
 
   int r0 = (int)nextKey.m_frame;
   int r1 = (int)nextNextKey.m_frame;
-
+  m_panel->update();
   m_sheet->getSelection()->selectSegment(m_curve, currentKeyIndex + 1,
                                          QRect(col, r0, 1, r1 - r0 + 1));
   m_sheet->updateAll();
diff --git a/toonz/sources/toonzqt/styleselection.cpp b/toonz/sources/toonzqt/styleselection.cpp
index 8a5d799..41b2a14 100644
--- a/toonz/sources/toonzqt/styleselection.cpp
+++ b/toonz/sources/toonzqt/styleselection.cpp
@@ -716,8 +716,9 @@ void TStyleSelection::eraseUnusedStyle() {
         for (j = 0; j < page->getStyleCount(); j++) {
           int styleId = page->getStyleId(j);
           if (m != 0 && usedStyleIds[styleId]) continue;
-          if (i == 0 && j == 0)  // Il primo stile della prima pagina non deve
-                                 // essere mai cancellato
+          if (i == 0 &&
+              (j == 0 || j == 1))  // Il primo stile della prima pagina non deve
+                                   // essere mai cancellato
           {
             usedStyleIds[styleId] = true;
             continue;