diff --git a/var/Slic3r-console.ico b/var/Slic3r-console.ico
new file mode 100644
index 000000000..64e818340
Binary files /dev/null and b/var/Slic3r-console.ico differ
diff --git a/xs/src/libslic3r/Layer.cpp b/xs/src/libslic3r/Layer.cpp
index 492eb8be4..d3399d46e 100644
--- a/xs/src/libslic3r/Layer.cpp
+++ b/xs/src/libslic3r/Layer.cpp
@@ -129,8 +129,19 @@ Layer::make_slices()
 void
 Layer::merge_slices()
 {
-    FOREACH_LAYERREGION(this, layerm) {
-        (*layerm)->merge_slices();
+    if (this->regions.size() == 1) {
+        // Optimization, also more robust. Don't merge classified pieces of layerm->slices,
+        // but use the non-split islands of a layer. For a single region print, these shall be equal.
+        this->regions.front()->slices.surfaces.clear();
+        surfaces_append(this->regions.front()->slices.surfaces, this->slices.expolygons, stInternal);
+    } else {
+        FOREACH_LAYERREGION(this, layerm) {
+            ExPolygons expp;
+            // without safety offset, artifacts are generated (GH #2494)
+            union_(to_polygons(STDMOVE((*layerm)->slices.surfaces)), &expp, true);
+            (*layerm)->slices.surfaces.clear();
+            surfaces_append((*layerm)->slices.surfaces, expp, stInternal);
+        }
     }
 }
 
diff --git a/xs/src/libslic3r/Layer.hpp b/xs/src/libslic3r/Layer.hpp
index 14957dd1c..e59f0c9e1 100644
--- a/xs/src/libslic3r/Layer.hpp
+++ b/xs/src/libslic3r/Layer.hpp
@@ -63,7 +63,6 @@ class LayerRegion
     ExtrusionEntityCollection fills;
     
     Flow flow(FlowRole role, bool bridge = false, double width = -1) const;
-    void merge_slices();
     void slices_to_fill_surfaces_clipped();
     void prepare_fill_surfaces();
     void make_perimeters(const SurfaceCollection &slices, SurfaceCollection* fill_surfaces);
diff --git a/xs/src/libslic3r/LayerRegion.cpp b/xs/src/libslic3r/LayerRegion.cpp
index a236c0389..7c84629e2 100644
--- a/xs/src/libslic3r/LayerRegion.cpp
+++ b/xs/src/libslic3r/LayerRegion.cpp
@@ -41,16 +41,6 @@ LayerRegion::flow(FlowRole role, bool bridge, double width) const
     );
 }
 
-void
-LayerRegion::merge_slices()
-{
-    ExPolygons expp;
-    // without safety offset, artifacts are generated (GH #2494)
-    union_(to_polygons(STDMOVE(this->slices.surfaces)), &expp, true);
-    this->slices.surfaces.clear();
-    surfaces_append(this->slices.surfaces, expp, stInternal);
-}
-
 // Fill in layerm->fill_surfaces by trimming the layerm->slices by the cummulative layerm->fill_surfaces.
 void LayerRegion::slices_to_fill_surfaces_clipped()
 {
@@ -126,6 +116,7 @@ LayerRegion::process_external_surfaces(const Layer* lower_layer)
     // Internal surfaces, not grown.
     Surfaces                    internal;
     // Areas, where an infill of various types (top, bottom, bottom bride, sparse, void) could be placed.
+    //FIXME if non zero infill, then fill_boundaries could be cheaply initialized from layerm->fill_expolygons.
     Polygons                    fill_boundaries;
 
     // Collect top surfaces and internal surfaces.