diff --git a/common/gal/cairo/cairo_gal.cpp b/common/gal/cairo/cairo_gal.cpp
index 242b509a7d..05f9dc2f64 100644
--- a/common/gal/cairo/cairo_gal.cpp
+++ b/common/gal/cairo/cairo_gal.cpp
@@ -1117,6 +1117,8 @@ void CAIRO_GAL_BASE::blitCursor( wxMemoryDC& clientDC )
 
 void CAIRO_GAL_BASE::drawPoly( const std::deque<VECTOR2D>& aPointList )
 {
+    wxCHECK( aPointList.size() > 2, /* void */ );
+
     // Iterate over the point list and draw the segments
     std::deque<VECTOR2D>::const_iterator it = aPointList.begin();
 
@@ -1140,6 +1142,8 @@ void CAIRO_GAL_BASE::drawPoly( const std::deque<VECTOR2D>& aPointList )
 
 void CAIRO_GAL_BASE::drawPoly( const VECTOR2D aPointList[], int aListSize )
 {
+    wxCHECK( aListSize > 2, /* void */ );
+
     // Iterate over the point list and draw the segments
     const VECTOR2D* ptr = aPointList;
 
@@ -1162,8 +1166,7 @@ void CAIRO_GAL_BASE::drawPoly( const VECTOR2D aPointList[], int aListSize )
 
 void CAIRO_GAL_BASE::drawPoly( const SHAPE_LINE_CHAIN& aLineChain )
 {
-    if( aLineChain.PointCount() < 2 )
-        return;
+    wxCHECK( aLineChain.PointCount() > 2, /* void */ );
 
     syncLineWidth();
 
diff --git a/common/gal/opengl/opengl_gal.cpp b/common/gal/opengl/opengl_gal.cpp
index ccd4349727..b2c7f98d9b 100644
--- a/common/gal/opengl/opengl_gal.cpp
+++ b/common/gal/opengl/opengl_gal.cpp
@@ -978,6 +978,7 @@ void OPENGL_GAL::DrawPolyline( const SHAPE_LINE_CHAIN& aLineChain )
 
 void OPENGL_GAL::DrawPolygon( const std::deque<VECTOR2D>& aPointList )
 {
+    wxCHECK( aPointList.size() > 2, /* void */ );
     auto points = std::unique_ptr<GLdouble[]>( new GLdouble[3 * aPointList.size()] );
     GLdouble* ptr = points.get();
 
@@ -994,6 +995,7 @@ void OPENGL_GAL::DrawPolygon( const std::deque<VECTOR2D>& aPointList )
 
 void OPENGL_GAL::DrawPolygon( const VECTOR2D aPointList[], int aListSize )
 {
+    wxCHECK( aListSize > 2, /* void */ );
     auto points = std::unique_ptr<GLdouble[]>( new GLdouble[3 * aListSize] );
     GLdouble* target = points.get();
     const VECTOR2D* src = aPointList;
@@ -1092,8 +1094,7 @@ void OPENGL_GAL::DrawPolygon( const SHAPE_POLY_SET& aPolySet )
 
 void OPENGL_GAL::DrawPolygon( const SHAPE_LINE_CHAIN& aPolygon )
 {
-    if( aPolygon.SegmentCount() == 0 )
-        return;
+    wxCHECK( aPolygon.PointCount() > 2, /* void */ );
 
     const int pointCount = aPolygon.SegmentCount() + 1;
     std::unique_ptr<GLdouble[]> points( new GLdouble[3 * pointCount] );