diff --git a/src/libslic3r/ClipperUtils.cpp b/src/libslic3r/ClipperUtils.cpp
index c6617002a..b2c5bd89e 100644
--- a/src/libslic3r/ClipperUtils.cpp
+++ b/src/libslic3r/ClipperUtils.cpp
@@ -705,6 +705,8 @@ Slic3r::Polylines diff_pl(const Slic3r::Polylines &subject, const Slic3r::Polygo
     { return _clipper_pl_open(ClipperLib::ctDifference, ClipperUtils::PolylinesProvider(subject), ClipperUtils::PolygonsProvider(clip)); }
 Slic3r::Polylines diff_pl(const Slic3r::Polyline &subject, const Slic3r::ExPolygon &clip)
     { return _clipper_pl_open(ClipperLib::ctDifference, ClipperUtils::SinglePathProvider(subject.points), ClipperUtils::ExPolygonProvider(clip)); }
+Slic3r::Polylines diff_pl(const Slic3r::Polyline &subject, const Slic3r::ExPolygons &clip)
+    { return _clipper_pl_open(ClipperLib::ctDifference, ClipperUtils::SinglePathProvider(subject.points), ClipperUtils::ExPolygonsProvider(clip)); }
 Slic3r::Polylines diff_pl(const Slic3r::Polylines &subject, const Slic3r::ExPolygon &clip)
     { return _clipper_pl_open(ClipperLib::ctDifference, ClipperUtils::PolylinesProvider(subject), ClipperUtils::ExPolygonProvider(clip)); }
 Slic3r::Polylines diff_pl(const Slic3r::Polylines &subject, const Slic3r::ExPolygons &clip)
diff --git a/src/libslic3r/ClipperUtils.hpp b/src/libslic3r/ClipperUtils.hpp
index d913154e0..e585e3011 100644
--- a/src/libslic3r/ClipperUtils.hpp
+++ b/src/libslic3r/ClipperUtils.hpp
@@ -408,6 +408,7 @@ Slic3r::ExPolygons diff_ex(const Slic3r::Surfaces &subject, const Slic3r::Surfac
 Slic3r::ExPolygons diff_ex(const Slic3r::SurfacesPtr &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
 Slic3r::Polylines  diff_pl(const Slic3r::Polylines &subject, const Slic3r::Polygons &clip);
 Slic3r::Polylines  diff_pl(const Slic3r::Polyline &subject, const Slic3r::ExPolygon &clip);
+Slic3r::Polylines  diff_pl(const Slic3r::Polyline &subject, const Slic3r::ExPolygons &clip);
 Slic3r::Polylines  diff_pl(const Slic3r::Polylines &subject, const Slic3r::ExPolygon &clip);
 Slic3r::Polylines  diff_pl(const Slic3r::Polylines &subject, const Slic3r::ExPolygons &clip);
 Slic3r::Polylines  diff_pl(const Slic3r::Polygons &subject, const Slic3r::Polygons &clip);
diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index d836ac43c..80aac2691 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -3137,7 +3137,7 @@ bool GCode::needs_retraction(const Polyline &travel, ExtrusionRole role)
     if (role == erSupportMaterial) {
         const SupportLayer* support_layer = dynamic_cast<const SupportLayer*>(m_layer);
         //FIXME support_layer->support_islands.contains should use some search structure!
-        if (support_layer != NULL && ! intersection_pl(travel, support_layer->support_islands).empty())
+        if (support_layer != NULL && diff_pl(travel, support_layer->support_islands).empty())
             // skip retraction if this is a travel move inside a support material island
             //FIXME not retracting over a long path may cause oozing, which in turn may result in missing material
             // at the end of the extrusion path!