diff --git a/toonz/sources/common/tgl/tgl.cpp b/toonz/sources/common/tgl/tgl.cpp
index 705c47a..88c6989 100644
--- a/toonz/sources/common/tgl/tgl.cpp
+++ b/toonz/sources/common/tgl/tgl.cpp
@@ -123,34 +123,6 @@ void tglDrawSegment(const TPointD &p1, const TPointD &p2) {
 
 //-----------------------------------------------------------------------------
 
-void tglDrawDoubleSegment(const TPointD &p1, const TPointD &p2) {
-  double color[4] = {};
-  double width = 1.0;
-  glGetDoublev(GL_CURRENT_COLOR, color);
-  glGetDoublev(GL_LINE_WIDTH, &width);
-  if (width < 1.0) width = 1.0;
-
-  TPointD d = p2 - p1;
-  double k = sqrt(d.x*d.x + d.y*d.y);
-  if (k <= 1e-9) return;
-  k = 0.5*width/k;
-  TPointD offset(-k*d.y, k*d.x);
-
-  glColor4d(1.0 - color[0], 1.0 - color[1], 1.0 - color[2], color[3]);
-  glBegin(GL_LINES);
-  tglVertex(p1 - offset);
-  tglVertex(p2 - offset);
-  glEnd();
-
-  glColor4dv(color);
-  glBegin(GL_LINES);
-  tglVertex(p1 + offset);
-  tglVertex(p2 + offset);
-  glEnd();
-}
-
-//-----------------------------------------------------------------------------
-
 void tglDrawCircle(const TPointD &center, double radius) {
   if (radius <= 0) return;
 
diff --git a/toonz/sources/include/tgl.h b/toonz/sources/include/tgl.h
index 67435ea..5c993b1 100644
--- a/toonz/sources/include/tgl.h
+++ b/toonz/sources/include/tgl.h
@@ -141,11 +141,6 @@ DVAPI void tglDrawDisk(const TPointD &c, double r);
  */
 DVAPI void tglDrawSegment(const TPointD &p1, const TPointD &p2);
 
-/*!
- Draw a segment pair - positive and negative.
- */
-DVAPI void tglDrawDoubleSegment(const TPointD &p1, const TPointD &p2);
-
 inline void tglDrawSegment(const TPoint &p1, const TPoint &p2) {
   tglDrawSegment(convert(p1), convert(p2));
 }
diff --git a/toonz/sources/tnztools/inputmanager.cpp b/toonz/sources/tnztools/inputmanager.cpp
index 76ef14a..0cb6bc7 100644
--- a/toonz/sources/tnztools/inputmanager.cpp
+++ b/toonz/sources/tnztools/inputmanager.cpp
@@ -638,6 +638,9 @@ TInputManager::draw() {
     glPushAttrib(GL_ALL_ATTRIB_BITS);
     tglEnableBlending();
     tglEnableLineSmooth(true, 0.5);
+    double pixelSize = sqrt(tglGetPixelSize2());
+    double colorBlack[4] = { 0.0, 0.0, 0.0, 1.0 };
+    double colorWhite[4] = { 1.0, 1.0, 1.0, 1.0 };
     for(TTrackList::const_iterator ti = getOutputTracks().begin(); ti != getOutputTracks().end(); ++ti) {
       TTrack &track = **ti;
       if (TrackHandler *handler = dynamic_cast<TrackHandler*>(track.handler.getPointer())) {
@@ -645,14 +648,24 @@ TInputManager::draw() {
         if (start < 0) start = 0;
         if (start + 1 < track.size()) {
           int level = m_savePointsSent;
-          double alpha = 1.0;
-          glColor4d(1.0, 1.0, 1.0, alpha);
+          colorBlack[3] = (colorWhite[3] = 0.8);
           for(int i = start + 1; i < track.size(); ++i) {
-            while(level < (int)handler->saves.size() && handler->saves[level] <= i) {
-              glColor4d(1.0, 1.0, 1.0, alpha *= 1.0);
-              ++level;
+            while(level < (int)handler->saves.size() && handler->saves[level] <= i)
+              colorBlack[3] = (colorWhite[3] *= 0.8), ++level;
+
+            const TPointD &a = track[i-1].position;
+            const TPointD &b = track[i].position;
+            TPointD d = b - a;
+
+            double k = norm2(d);
+            if (k > TConsts::epsilon*TConsts::epsilon) {
+              double k = 0.5*pixelSize/sqrt(k);
+              d = TPointD(-k*d.y, k*d.x);
+              glColor4dv(colorWhite);
+              tglDrawSegment(a - d, b - d);
+              glColor4dv(colorBlack);
+              tglDrawSegment(a + d, b + d);
             }
-            tglDrawDoubleSegment(track[i-1].position, track[i].position);
           }
         }
       }