diff --git a/toonz/sources/common/trop/quickput.cpp b/toonz/sources/common/trop/quickput.cpp
index 7895288..253c334 100644
--- a/toonz/sources/common/trop/quickput.cpp
+++ b/toonz/sources/common/trop/quickput.cpp
@@ -3233,12 +3233,17 @@ void doQuickPutCmapped(const TRaster32P &dn, const TRasterCM32P &up,
   std::vector<TPixel32> paints(palette->getStyleCount());
   std::vector<TPixel32> inks(palette->getStyleCount());
 
-  if (s.m_transparencyCheck)
+  if (s.m_transparencyCheck && !s.m_isOnionSkin) {
     for (int i = 0; i < palette->getStyleCount(); i++) {
-      paints[i] = s.m_transpCheckPaint;
-      inks[i]   = s.m_blackBgCheck ? s.m_transpCheckBg : s.m_transpCheckInk;
+      if (i == s.m_gapCheckIndex) {
+        paints[i] = inks[i] = applyColorScaleCMapped(
+            palette->getStyle(i)->getAverageColor(), s.m_globalColorScale);
+      } else {
+        paints[i] = s.m_transpCheckPaint;
+        inks[i]   = s.m_blackBgCheck ? s.m_transpCheckBg : s.m_transpCheckInk;
+      }
     }
-  else if (s.m_globalColorScale == TPixel::Black)
+  } else if (s.m_globalColorScale == TPixel::Black)
     for (int i  = 0; i < palette->getStyleCount(); i++)
       paints[i] = inks[i] =
           ::premultiply(palette->getStyle(i)->getAverageColor());
diff --git a/toonz/sources/include/trop.h b/toonz/sources/include/trop.h
index 2985147..9ba3ed3 100644
--- a/toonz/sources/include/trop.h
+++ b/toonz/sources/include/trop.h
@@ -178,13 +178,16 @@ public:
 
   int m_inkIndex, m_paintIndex;
 
-  bool m_inksOnly, m_transparencyCheck, m_blackBgCheck;
+  bool m_inksOnly, m_transparencyCheck, m_blackBgCheck, m_isOnionSkin;
+  int m_gapCheckIndex = -1;
 
   CmappedQuickputSettings()
       : m_globalColorScale(TPixel32::Black)
       , m_inksOnly(false)
       , m_transparencyCheck(false)
       , m_blackBgCheck(false)
+      , m_isOnionSkin(false)
+      , m_gapCheckIndex(-1)
       , m_inkIndex(-1)
       , m_paintIndex(-1) {}
 };
diff --git a/toonz/sources/tnztools/rastertapetool.cpp b/toonz/sources/tnztools/rastertapetool.cpp
index 109e294..6a6fb4b 100644
--- a/toonz/sources/tnztools/rastertapetool.cpp
+++ b/toonz/sources/tnztools/rastertapetool.cpp
@@ -205,7 +205,7 @@ public:
   }
 
   //------------------------------------------------------------
-  /*--  AutoCloseが実行されたらtrue,実行されなければfalseを返す --*/
+  /*--  AutoClose Returns true if executed, false otherwise --*/
   bool applyAutoclose(const TToonzImageP &ti, const TRectD &selRect = TRectD(),
                       TStroke *stroke = 0) {
     if (!ti) return false;
diff --git a/toonz/sources/tnztools/toonzrasterbrushtool.cpp b/toonz/sources/tnztools/toonzrasterbrushtool.cpp
index 7349416..56178a6 100644
--- a/toonz/sources/tnztools/toonzrasterbrushtool.cpp
+++ b/toonz/sources/tnztools/toonzrasterbrushtool.cpp
@@ -1516,6 +1516,8 @@ void ToonzRasterBrushTool::leftButtonUp(const TPointD &pos,
   TPointD centeredPos = getCenteredCursorPos(pos);
   double pressure = m_pressure.getValue() && e.isTablet() ? e.m_pressure : 0.5;
   finishRasterBrush(centeredPos, pressure);
+  int tc = ToonzCheck::instance()->getChecks();
+  if (tc & ToonzCheck::eGap || tc & ToonzCheck::eAutoclose) invalidate();
 }
 
 //---------------------------------------------------------------------------------------------------------------
diff --git a/toonz/sources/toonzlib/stagevisitor.cpp b/toonz/sources/toonzlib/stagevisitor.cpp
index 9f45f51..0864ad5 100644
--- a/toonz/sources/toonzlib/stagevisitor.cpp
+++ b/toonz/sources/toonzlib/stagevisitor.cpp
@@ -261,13 +261,12 @@ void Picker::onImage(const Stage::Player &player) {
       double maxDist2  = maxDist * maxDist;
       double checkDist = maxDist2 * 4;
 
-      TStroke *stroke = vi->getStroke(strokeIndex);
+      TStroke *stroke        = vi->getStroke(strokeIndex);
       TThickPoint thickPoint = stroke->getThickPoint(w);
-      double thickness = thickPoint.thick;
-      double len = thickness * pixelSize * sqrt(m_viewAff.det());
-      checkDist = std::max(checkDist, (len * len));
-      if (dist2 < checkDist)
-        picked = true;
+      double thickness       = thickPoint.thick;
+      double len             = thickness * pixelSize * sqrt(m_viewAff.det());
+      checkDist              = std::max(checkDist, (len * len));
+      if (dist2 < checkDist) picked = true;
     }
   } else if (TRasterImageP ri = img) {
     TRaster32P ras = ri->getRaster();
@@ -574,11 +573,12 @@ void RasterPainter::flushRasterImages() {
       m_nodes[i].m_palette->setFrame(m_nodes[i].m_frame);
 
       TPaletteP plt;
+      int styleIndex = -1;
       if ((tc & ToonzCheck::eGap || tc & ToonzCheck::eAutoclose) &&
           m_nodes[i].m_isCurrentColumn) {
-        srcCm          = srcCm->clone();
-        plt            = m_nodes[i].m_palette->clone();
-        int styleIndex = plt->addStyle(TPixel::Magenta);
+        srcCm      = srcCm->clone();
+        plt        = m_nodes[i].m_palette->clone();
+        styleIndex = plt->addStyle(TPixel::Magenta);
         if (tc & ToonzCheck::eAutoclose)
           TAutocloser(srcCm, AutocloseDistance, AutocloseAngle, styleIndex,
                       AutocloseOpacity)
@@ -614,6 +614,9 @@ void RasterPainter::flushRasterImages() {
             settings.m_transpCheckBg, settings.m_transpCheckInk,
             settings.m_transpCheckPaint);
 
+        settings.m_isOnionSkin = m_nodes[i].m_onionMode != Node::eOnionSkinNone;
+        settings.m_gapCheckIndex = styleIndex;
+
         TRop::quickPut(viewedRaster, srcCm, plt, aff, settings);
       }
 
@@ -661,7 +664,7 @@ void RasterPainter::flushRasterImages() {
 #endif
 
 #ifdef GL_EXT_texture3D
-  if( GL_EXT_texture3D ) {
+  if (GL_EXT_texture3D) {
     glDisable(GL_TEXTURE_3D_EXT);
   }
 #endif
@@ -768,7 +771,7 @@ static void drawAutocloses(TVectorImage *vi, TVectorRenderData &rd) {
   buildAutocloseImage(vaux, vi, startPoints, endPoints);
   // temporarily disable fill check, to preserve the gap indicator color
   bool tCheckEnabledOriginal = rd.m_tcheckEnabled;
-  rd.m_tcheckEnabled = false;
+  rd.m_tcheckEnabled         = false;
   // draw
   tglDraw(rd, vaux);
   // restore original value
@@ -1075,11 +1078,11 @@ void RasterPainter::onToonzImage(TToonzImage *ti, const Stage::Player &player) {
   int alpha                 = 255;
   Node::OnionMode onionMode = Node::eOnionSkinNone;
   if (player.m_onionSkinDistance != c_noOnionSkin) {
-    // GetOnionSkinFade va bene per il vettoriale mentre il raster funziona al
-    // contrario
-    // 1 opaco -> 0 completamente trasparente
-    // inverto quindi il risultato della funzione stando attento al caso 0
-    // (in cui era scolpito il valore 0.9)
+    // GetOnionSkinFade is good for the vector while the raster works at the
+    //    Opposite 1 opaque -> 0 completely transparent
+    //    I therefore reverse the result of the function by being attentive to
+    //    case 0
+    //    (where the value 0.9 was carved)
     double onionSkiFade = player.m_onionSkinDistance == 0
                               ? 0.9
                               : (1.0 - OnionSkinMask::getOnionSkinFade(