diff --git a/resources/models/mk2_bed.stl b/resources/models/mk2_bed.stl
new file mode 100644
index 000000000..07b7655ea
Binary files /dev/null and b/resources/models/mk2_bed.stl differ
diff --git a/resources/models/mk3_bed.stl b/resources/models/mk3_bed.stl
new file mode 100644
index 000000000..cfa6d8c6d
Binary files /dev/null and b/resources/models/mk3_bed.stl differ
diff --git a/src/libslic3r/Config.cpp b/src/libslic3r/Config.cpp
index 2f61cc008..c295d6def 100644
--- a/src/libslic3r/Config.cpp
+++ b/src/libslic3r/Config.cpp
@@ -404,7 +404,7 @@ void ConfigBase::load_from_gcode_file(const std::string &file)
 
     size_t key_value_pairs = load_from_gcode_string(data.data());
     if (key_value_pairs < 80)
-        throw std::runtime_error((boost::format("Suspiciously low number of configuration values extracted from %1: %2") % file % key_value_pairs).str());
+        throw std::runtime_error((boost::format("Suspiciously low number of configuration values extracted from %1%: %2%") % file % key_value_pairs).str());
 }
 
 // Load the config keys from the given string.
@@ -536,7 +536,7 @@ void DynamicConfig::read_cli(const std::vector<std::string> &tokens, t_config_op
     args.emplace_back(const_cast<char*>(""));
     for (size_t i = 0; i < tokens.size(); ++ i)
         args.emplace_back(const_cast<char *>(tokens[i].c_str()));
-    this->read_cli(args.size(), &args[0], extra);
+    this->read_cli(int(args.size()), &args[0], extra);
 }
 
 bool DynamicConfig::read_cli(int argc, char** argv, t_config_option_keys* extra)
diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index 4704c65f3..739c918c1 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -791,7 +791,7 @@ void GCode::_do_export(Print &print, FILE *file)
         }
     } else {
         for (const std::string &start_gcode : print.config().start_filament_gcode.values)
-            _writeln(file, this->placeholder_parser_process("start_gcode", start_gcode, (unsigned int)(&start_gcode - &print.config().start_filament_gcode.values.front())));
+            _writeln(file, this->placeholder_parser_process("start_filament_gcode", start_gcode, (unsigned int)(&start_gcode - &print.config().start_filament_gcode.values.front())));
     }
     this->_print_first_layer_extruder_temperatures(file, print, start_gcode, initial_extruder_id, true);
     print.throw_if_canceled();
diff --git a/src/libslic3r/Geometry.cpp b/src/libslic3r/Geometry.cpp
index 55ce3fa2c..ffaee3135 100644
--- a/src/libslic3r/Geometry.cpp
+++ b/src/libslic3r/Geometry.cpp
@@ -927,9 +927,9 @@ Vec3d extract_euler_angles(const Eigen::Matrix<double, 3, 3, Eigen::DontAlign>&
     }
     else
     {
-        angles(0) = ::atan2(-rotation_matrix(1, 2), rotation_matrix(1, 1));
+        angles(1) = 0.0;
         angles(1) = ::atan2(-rotation_matrix(2, 0), sy);
-        angles(2) = 0.0;
+        angles(2) = (angles(1) >-0.0) ? ::atan2(rotation_matrix(1, 2), rotation_matrix(1, 1)) : ::atan2(-rotation_matrix(1, 2), rotation_matrix(1, 1));
     }
 
     return angles;
diff --git a/src/libslic3r/Model.cpp b/src/libslic3r/Model.cpp
index 20c4a44b2..900397f70 100644
--- a/src/libslic3r/Model.cpp
+++ b/src/libslic3r/Model.cpp
@@ -719,12 +719,13 @@ ModelInstance* ModelObject::add_instance(const ModelInstance &other)
     return i;
 }
 
-ModelInstance* ModelObject::add_instance(const Vec3d &offset, const Vec3d &scaling_factor, const Vec3d &rotation)
+ModelInstance* ModelObject::add_instance(const Vec3d &offset, const Vec3d &scaling_factor, const Vec3d &rotation, const Vec3d &mirror)
 {
     auto *instance = add_instance();
     instance->set_offset(offset);
     instance->set_scaling_factor(scaling_factor);
     instance->set_rotation(rotation);
+    instance->set_mirror(mirror);
     return instance;
 }
 
diff --git a/src/libslic3r/Model.hpp b/src/libslic3r/Model.hpp
index e65228d80..947301437 100644
--- a/src/libslic3r/Model.hpp
+++ b/src/libslic3r/Model.hpp
@@ -200,7 +200,7 @@ public:
 
     ModelInstance*          add_instance();
     ModelInstance*          add_instance(const ModelInstance &instance);
-    ModelInstance*          add_instance(const Vec3d &offset, const Vec3d &scaling_factor, const Vec3d &rotation);
+    ModelInstance*          add_instance(const Vec3d &offset, const Vec3d &scaling_factor, const Vec3d &rotation, const Vec3d &mirror);
     void                    delete_instance(size_t idx);
     void                    delete_last_instance();
     void                    clear_instances();
diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index 2e9059807..625613213 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -3416,6 +3416,13 @@ CLIConfigDef::CLIConfigDef()
 const CLIConfigDef cli_config_def;
 DynamicPrintAndCLIConfig::PrintAndCLIConfigDef DynamicPrintAndCLIConfig::s_def;
 
+void DynamicPrintAndCLIConfig::handle_legacy(t_config_option_key &opt_key, std::string &value) const
+{
+    if (cli_config_def.options.find(opt_key) == cli_config_def.options.end()) {
+        PrintConfigDef::handle_legacy(opt_key, value);
+    }
+}
+
 std::ostream& print_cli_options(std::ostream& out)
 {
     for (const auto& opt : cli_config_def.options) {
diff --git a/src/libslic3r/PrintConfig.hpp b/src/libslic3r/PrintConfig.hpp
index 4c88f3a18..b96176fe5 100644
--- a/src/libslic3r/PrintConfig.hpp
+++ b/src/libslic3r/PrintConfig.hpp
@@ -1241,6 +1241,12 @@ public:
     const ConfigDef*        def() const override { return &s_def; }
     t_config_option_keys    keys() const override { return s_def.keys(); }
 
+    // Verify whether the opt_key has not been obsoleted or renamed.
+    // Both opt_key and value may be modified by handle_legacy().
+    // If the opt_key is no more valid in this version of Slic3r, opt_key is cleared by handle_legacy().
+    // handle_legacy() is called internally by set_deserialize().
+    void                    handle_legacy(t_config_option_key &opt_key, std::string &value) const override;
+
 private:
     class PrintAndCLIConfigDef : public ConfigDef
     {
diff --git a/src/libslic3r/Technologies.hpp b/src/libslic3r/Technologies.hpp
index c32fe3e8d..bab7f3b73 100644
--- a/src/libslic3r/Technologies.hpp
+++ b/src/libslic3r/Technologies.hpp
@@ -42,8 +42,10 @@
 //====================
 #define ENABLE_1_42_0_ALPHA2 1
 
+// Improves navigation between sidebar fields
 #define ENABLE_IMPROVED_SIDEBAR_OBJECTS_MANIPULATION (1 && ENABLE_1_42_0_ALPHA2)
-
+// Adds print bed models to 3D scene
+#define ENABLE_PRINT_BED_MODELS (0 && ENABLE_1_42_0_ALPHA2)
 #endif // _technologies_h_
 
 
diff --git a/src/slic3r/GUI/3DScene.cpp b/src/slic3r/GUI/3DScene.cpp
index 42b025093..d44789b7a 100644
--- a/src/slic3r/GUI/3DScene.cpp
+++ b/src/slic3r/GUI/3DScene.cpp
@@ -11,6 +11,9 @@
 #include "libslic3r/Slicing.hpp"
 #include "libslic3r/GCode/Analyzer.hpp"
 #include "slic3r/GUI/PresetBundle.hpp"
+#if ENABLE_PRINT_BED_MODELS
+#include "libslic3r/Format/STL.hpp"
+#endif // ENABLE_PRINT_BED_MODELS
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -20,6 +23,11 @@
 
 #include <boost/log/trivial.hpp>
 
+#if ENABLE_PRINT_BED_MODELS
+#include <boost/filesystem/operations.hpp>
+#include <boost/algorithm/string.hpp>
+#endif // ENABLE_PRINT_BED_MODELS
+
 #include <tbb/parallel_for.h>
 #include <tbb/spin_mutex.h>
 
@@ -249,11 +257,7 @@ void GLVolume::set_render_color(float r, float g, float b, float a)
 
 void GLVolume::set_render_color(const float* rgba, unsigned int size)
 {
-    size = std::min((unsigned int)4, size);
-    for (unsigned int i = 0; i < size; ++i)
-    {
-        render_color[i] = rgba[i];
-    }
+    ::memcpy((void*)render_color, (const void*)rgba, (size_t)(std::min((unsigned int)4, size) * sizeof(float)));
 }
 
 void GLVolume::set_render_color()
@@ -1790,17 +1794,27 @@ GUI::GLCanvas3DManager _3DScene::s_canvas_mgr;
 #if ENABLE_SIDEBAR_VISUAL_HINTS
 GLModel::GLModel()
     : m_useVBOs(false)
+#if ENABLE_PRINT_BED_MODELS
+    , m_filename("")
+#endif // ENABLE_PRINT_BED_MODELS
 {
     m_volume.shader_outside_printer_detection_enabled = false;
 }
 
 GLModel::~GLModel()
 {
+#if ENABLE_PRINT_BED_MODELS
+    reset();
+#else
     m_volume.release_geometry();
+#endif // ENABLE_PRINT_BED_MODELS
 }
 
 void GLModel::set_color(const float* color, unsigned int size)
 {
+#if ENABLE_PRINT_BED_MODELS
+    ::memcpy((void*)m_volume.color, (const void*)color, (size_t)(std::min((unsigned int)4, size) * sizeof(float)));
+#endif // ENABLE_PRINT_BED_MODELS
     m_volume.set_render_color(color, size);
 }
 
@@ -1834,6 +1848,14 @@ void GLModel::set_scale(const Vec3d& scale)
     m_volume.set_volume_scaling_factor(scale);
 }
 
+#if ENABLE_PRINT_BED_MODELS
+void GLModel::reset()
+{
+    m_volume.release_geometry();
+    m_filename = "";
+}
+#endif // ENABLE_PRINT_BED_MODELS
+
 void GLModel::render() const
 {
     if (m_useVBOs)
@@ -1854,9 +1876,7 @@ void GLModel::render_VBOs() const
     GLint current_program_id;
     ::glGetIntegerv(GL_CURRENT_PROGRAM, &current_program_id);
     GLint color_id = (current_program_id > 0) ? glGetUniformLocation(current_program_id, "uniform_color") : -1;
-    GLint print_box_detection_id = (current_program_id > 0) ? glGetUniformLocation(current_program_id, "print_box.volume_detection") : -1;
-
-    m_volume.render_VBOs(color_id, print_box_detection_id, -1);
+    m_volume.render_VBOs(color_id, -1, -1);
 
     ::glBindBuffer(GL_ARRAY_BUFFER, 0);
     ::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
@@ -2066,11 +2086,57 @@ bool GLCurvedArrow::on_init(bool useVBOs)
     else
         m_volume.indexed_vertex_array.load_mesh_flat_shading(TriangleMesh(vertices, triangles));
 
+    m_volume.bounding_box = m_volume.indexed_vertex_array.bounding_box();
     m_volume.finalize_geometry(m_useVBOs);
     return true;
 }
 #endif // ENABLE_SIDEBAR_VISUAL_HINTS
 
+#if ENABLE_PRINT_BED_MODELS
+bool GLBed::on_init_from_file(const std::string& filename, bool useVBOs)
+{
+    reset();
+
+    if (!boost::filesystem::exists(filename))
+        return false;
+
+    if (!boost::algorithm::iends_with(filename, ".stl"))
+        return false;
+
+    Model model;
+    try
+    {
+        model = Model::read_from_file(filename);
+    }
+    catch (std::exception &e)
+    {
+        return false;
+    }
+
+    m_filename = filename;
+    m_useVBOs = useVBOs;
+
+    ModelObject* model_object = model.objects.front();
+    model_object->center_around_origin();
+
+    TriangleMesh mesh = model.mesh();
+    mesh.repair();
+
+    if (m_useVBOs)
+        m_volume.indexed_vertex_array.load_mesh_full_shading(mesh);
+    else
+        m_volume.indexed_vertex_array.load_mesh_flat_shading(mesh);
+
+    float color[4] = { 0.235f, 0.235, 0.235f, 1.0f };
+    set_color(color, 4);
+
+    m_volume.bounding_box = m_volume.indexed_vertex_array.bounding_box();
+    m_volume.finalize_geometry(m_useVBOs);
+
+    return true;
+}
+#endif // ENABLE_PRINT_BED_MODELS
+
 std::string _3DScene::get_gl_info(bool format_as_html, bool extensions)
 {
     return s_canvas_mgr.get_gl_info(format_as_html, extensions);
diff --git a/src/slic3r/GUI/3DScene.hpp b/src/slic3r/GUI/3DScene.hpp
index 38996dc04..b7b1af73d 100644
--- a/src/slic3r/GUI/3DScene.hpp
+++ b/src/slic3r/GUI/3DScene.hpp
@@ -569,13 +569,20 @@ class GLModel
 protected:
     GLVolume m_volume;
     bool m_useVBOs;
+#if ENABLE_PRINT_BED_MODELS
+    std::string m_filename;
+#endif // ENABLE_PRINT_BED_MODELS
 
 public:
     GLModel();
     virtual ~GLModel();
 
     bool init(bool useVBOs) { return on_init(useVBOs); }
+#if ENABLE_PRINT_BED_MODELS
+    bool init_from_file(const std::string& filename, bool useVBOs) { return on_init_from_file(filename, useVBOs); }
 
+    void center_around(const Vec3d& center) { m_volume.set_volume_offset(center - m_volume.bounding_box.center()); }
+#endif // ENABLE_PRINT_BED_MODELS
     void set_color(const float* color, unsigned int size);
 
     const Vec3d& get_offset() const;
@@ -585,10 +592,22 @@ public:
     const Vec3d& get_scale() const;
     void set_scale(const Vec3d& scale);
 
+#if ENABLE_PRINT_BED_MODELS
+    const std::string& get_filename() const { return m_filename; }
+    const BoundingBoxf3& get_bounding_box() const { return m_volume.bounding_box; }
+
+    void reset();
+#endif // ENABLE_PRINT_BED_MODELS
+
     void render() const; 
 
 protected:
+#if ENABLE_PRINT_BED_MODELS
+    virtual bool on_init(bool useVBOs) { return false; }
+    virtual bool on_init_from_file(const std::string& filename, bool useVBOs) { return false; }
+#else
     virtual bool on_init(bool useVBOs) = 0;
+#endif // ENABLE_PRINT_BED_MODELS
 
 private:
     void render_VBOs() const;
@@ -613,6 +632,14 @@ protected:
 };
 #endif // ENABLE_SIDEBAR_VISUAL_HINTS
 
+#if ENABLE_PRINT_BED_MODELS
+class GLBed : public GLModel
+{
+protected:
+    virtual bool on_init_from_file(const std::string& filename, bool useVBOs);
+};
+#endif // ENABLE_PRINT_BED_MODELS
+
 class _3DScene
 {
     static GUI::GLCanvas3DManager s_canvas_mgr;
diff --git a/src/slic3r/GUI/BackgroundSlicingProcess.cpp b/src/slic3r/GUI/BackgroundSlicingProcess.cpp
index 44ac1bc71..4ef020bf8 100644
--- a/src/slic3r/GUI/BackgroundSlicingProcess.cpp
+++ b/src/slic3r/GUI/BackgroundSlicingProcess.cpp
@@ -126,7 +126,7 @@ public:
     }
 
     inline std::string get_name() const {
-        return fpath.GetName().ToStdString();
+        return fpath.GetName().ToUTF8().data();
     }
 
     template<class T> inline LayerWriter& operator<<(const T& arg) {
diff --git a/src/slic3r/GUI/BedShapeDialog.cpp b/src/slic3r/GUI/BedShapeDialog.cpp
index dbc9e36d8..feb44a922 100644
--- a/src/slic3r/GUI/BedShapeDialog.cpp
+++ b/src/slic3r/GUI/BedShapeDialog.cpp
@@ -305,7 +305,7 @@ void BedShapePanel::load_stl()
 	dialog->GetPaths(input_file);
 	dialog->Destroy();
 
-	std::string file_name = input_file[0].ToStdString();
+	std::string file_name = input_file[0].ToUTF8().data();
 
 	Model model;
 	try {
diff --git a/src/slic3r/GUI/ConfigWizard.cpp b/src/slic3r/GUI/ConfigWizard.cpp
index 028c0011c..b46f6ff93 100644
--- a/src/slic3r/GUI/ConfigWizard.cpp
+++ b/src/slic3r/GUI/ConfigWizard.cpp
@@ -73,8 +73,7 @@ PrinterPicker::PrinterPicker(wxWindow *parent, const VendorProfile &vendor, cons
 	std::vector<wxPanel*> variants_panels;
 
 	for (const auto &model : models) {
-		auto bitmap_file = wxString::Format("printers/%s_%s.png", vendor.id, model.id);
-		wxBitmap bitmap(GUI::from_u8(Slic3r::var(bitmap_file.ToStdString())), wxBITMAP_TYPE_PNG);
+		wxBitmap bitmap(GUI::from_u8(Slic3r::var((boost::format("printers/%1%_%2%.png") % vendor.id % model.id).str())), wxBITMAP_TYPE_PNG);
 
 		auto *title = new wxStaticText(this, wxID_ANY, model.name, wxDefaultPosition, wxDefaultSize, wxALIGN_LEFT);
 		title->SetFont(namefont);
diff --git a/src/slic3r/GUI/Field.cpp b/src/slic3r/GUI/Field.cpp
index e1bec8578..501d1f1bc 100644
--- a/src/slic3r/GUI/Field.cpp
+++ b/src/slic3r/GUI/Field.cpp
@@ -188,7 +188,7 @@ void Field::get_value_by_opt_type(wxString& str)
             }
         }
     
-        m_value = str.ToStdString();
+        m_value = str.ToUTF8().data();
 		break; }
 	default:
 		break;
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 1ed266d09..48e87f66e 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -386,6 +386,35 @@ Point GLCanvas3D::Bed::point_projection(const Point& point) const
     return m_polygon.point_projection(point);
 }
 
+#if ENABLE_PRINT_BED_MODELS
+void GLCanvas3D::Bed::render(float theta, bool useVBOs) const
+{
+    switch (m_type)
+    {
+    case MK2:
+    {
+        _render_prusa("mk2", theta, useVBOs);
+        break;
+    }
+    case MK3:
+    {
+        _render_prusa("mk3", theta, useVBOs);
+        break;
+    }
+    case SL1:
+    {
+        _render_prusa("sl1", theta, useVBOs);
+        break;
+    }
+    default:
+    case Custom:
+    {
+        _render_custom();
+        break;
+    }
+    }
+}
+#else
 void GLCanvas3D::Bed::render(float theta) const
 {
     switch (m_type)
@@ -413,6 +442,7 @@ void GLCanvas3D::Bed::render(float theta) const
     }
     }
 }
+#endif // ENABLE_PRINT_BED_MODELS
 
 void GLCanvas3D::Bed::_calc_bounding_box()
 {
@@ -504,9 +534,18 @@ GLCanvas3D::Bed::EType GLCanvas3D::Bed::_detect_type() const
     return type;
 }
 
+#if ENABLE_PRINT_BED_MODELS
+void GLCanvas3D::Bed::_render_prusa(const std::string &key, float theta, bool useVBOs) const
+#else
 void GLCanvas3D::Bed::_render_prusa(const std::string &key, float theta) const
+#endif // ENABLE_PRINT_BED_MODELS
 {
-    std::string filename = resources_dir() + "/icons/bed/" + key + "_top.png";
+    std::string tex_path = resources_dir() + "/icons/bed/" + key;
+#if ENABLE_PRINT_BED_MODELS
+    std::string model_path = resources_dir() + "/models/" + key;
+#endif // ENABLE_PRINT_BED_MODELS
+
+    std::string filename = tex_path + "_top.png";
     if ((m_top_texture.get_id() == 0) || (m_top_texture.get_source() != filename))
     {
         if (!m_top_texture.load_from_file(filename, true))
@@ -516,7 +555,7 @@ void GLCanvas3D::Bed::_render_prusa(const std::string &key, float theta) const
         }
     }
 
-    filename = resources_dir() + "/icons/bed/" + key + "_bottom.png";
+    filename = tex_path + "_bottom.png";
     if ((m_bottom_texture.get_id() == 0) || (m_bottom_texture.get_source() != filename))
     {
         if (!m_bottom_texture.load_from_file(filename, true))
@@ -526,6 +565,22 @@ void GLCanvas3D::Bed::_render_prusa(const std::string &key, float theta) const
         }
     }
 
+#if ENABLE_PRINT_BED_MODELS
+    if (theta <= 90.0f)
+    {
+        filename = model_path + "_bed.stl";
+        if ((m_model.get_filename() != filename) && m_model.init_from_file(filename, useVBOs))
+            m_model.center_around(m_bounding_box.center() - Vec3d(0.0, 0.0, 1.0 + 0.5 * m_model.get_bounding_box().size()(2)));
+
+        if (!m_model.get_filename().empty())
+        {
+            ::glEnable(GL_LIGHTING);
+            m_model.render();
+            ::glDisable(GL_LIGHTING);
+        }
+    }
+#endif // ENABLE_PRINT_BED_MODELS
+
     unsigned int triangles_vcount = m_triangles.get_vertices_count();
     if (triangles_vcount > 0)
     {
@@ -4896,6 +4951,7 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
         }
 
         m_mouse.set_start_position_2D_as_invalid();
+        m_mouse.set_start_position_3D_as_invalid();
 #endif
     }
     else if (evt.Leaving())
@@ -6086,7 +6142,11 @@ void GLCanvas3D::_render_background() const
 
 void GLCanvas3D::_render_bed(float theta) const
 {
+#if ENABLE_PRINT_BED_MODELS
+    m_bed.render(theta, m_use_VBOs);
+#else
     m_bed.render(theta);
+#endif // ENABLE_PRINT_BED_MODELS
 }
 
 void GLCanvas3D::_render_axes() const
diff --git a/src/slic3r/GUI/GLCanvas3D.hpp b/src/slic3r/GUI/GLCanvas3D.hpp
index 73aa4bd02..c2f2074c1 100644
--- a/src/slic3r/GUI/GLCanvas3D.hpp
+++ b/src/slic3r/GUI/GLCanvas3D.hpp
@@ -201,6 +201,9 @@ class GLCanvas3D
         GeometryBuffer m_gridlines;
         mutable GLTexture m_top_texture;
         mutable GLTexture m_bottom_texture;
+#if ENABLE_PRINT_BED_MODELS
+        mutable GLBed m_model;
+#endif // ENABLE_PRINT_BED_MODELS
 
     public:
         Bed();
@@ -216,14 +219,22 @@ class GLCanvas3D
         bool contains(const Point& point) const;
         Point point_projection(const Point& point) const;
 
+#if ENABLE_PRINT_BED_MODELS
+        void render(float theta, bool useVBOs) const;
+#else
         void render(float theta) const;
+#endif // ENABLE_PRINT_BED_MODELS
 
     private:
         void _calc_bounding_box();
         void _calc_triangles(const ExPolygon& poly);
         void _calc_gridlines(const ExPolygon& poly, const BoundingBox& bed_bbox);
         EType _detect_type() const;
+#if ENABLE_PRINT_BED_MODELS
+        void _render_prusa(const std::string &key, float theta, bool useVBOs) const;
+#else
         void _render_prusa(const std::string &key, float theta) const;
+#endif // ENABLE_PRINT_BED_MODELS
         void _render_custom() const;
         static bool _are_equal(const Pointfs& bed_1, const Pointfs& bed_2);
     };
diff --git a/src/slic3r/GUI/GUI_App.cpp b/src/slic3r/GUI/GUI_App.cpp
index b1ecef7df..091071e16 100644
--- a/src/slic3r/GUI/GUI_App.cpp
+++ b/src/slic3r/GUI/GUI_App.cpp
@@ -461,10 +461,8 @@ bool GUI_App::select_language(  wxArrayString & names,
         m_wxLocale->Init(identifiers[index]);
 		m_wxLocale->AddCatalogLookupPathPrefix(wxString::FromUTF8(localization_dir()));
         m_wxLocale->AddCatalog(/*GetAppName()*/"Slic3rPE");
-        wxSetlocale(LC_NUMERIC, "C");
-#ifdef WIN32
-        ::SetLocaleInfoA(LOCALE_CUSTOM_DEFAULT, LOCALE_SDECIMAL, ".");
-#endif /* WIN32 */
+		//FIXME This is a temporary workaround, the correct solution is to switch to "C" locale during file import / export only.
+		wxSetlocale(LC_NUMERIC, "C");
         Preset::update_suffix_modified();
         return true;
     }
@@ -491,10 +489,8 @@ bool GUI_App::load_language()
             m_wxLocale->Init(identifiers[i]);
 			m_wxLocale->AddCatalogLookupPathPrefix(wxString::FromUTF8(localization_dir()));
             m_wxLocale->AddCatalog(/*GetAppName()*/"Slic3rPE");
+			//FIXME This is a temporary workaround, the correct solution is to switch to "C" locale during file import / export only.
             wxSetlocale(LC_NUMERIC, "C");
-#ifdef WIN32
-			::SetLocaleInfoA(LOCALE_CUSTOM_DEFAULT, LOCALE_SDECIMAL, ".");
-#endif /* WIN32 */
 			Preset::update_suffix_modified();
             return true;
         }
@@ -509,7 +505,7 @@ void GUI_App::save_language()
     if (m_wxLocale)
         language = m_wxLocale->GetCanonicalName();
 
-    app_config->set("translation_language", language.ToStdString());
+    app_config->set("translation_language", language.ToUTF8().data());
     app_config->save();
 }
 
diff --git a/src/slic3r/GUI/GUI_ObjectList.cpp b/src/slic3r/GUI/GUI_ObjectList.cpp
index afeaca327..dffaf7afc 100644
--- a/src/slic3r/GUI/GUI_ObjectList.cpp
+++ b/src/slic3r/GUI/GUI_ObjectList.cpp
@@ -298,13 +298,13 @@ void ObjectList::update_name_in_model(const wxDataViewItem& item)
     if (obj_idx < 0) return;
 
     if (m_objects_model->GetParent(item) == wxDataViewItem(0)) {
-        (*m_objects)[obj_idx]->name = m_objects_model->GetName(item).ToStdString();
+        (*m_objects)[obj_idx]->name = m_objects_model->GetName(item).ToUTF8().data();
         return;
     }
 
     const int volume_id = m_objects_model->GetVolumeIdByItem(item);
     if (volume_id < 0) return;
-    (*m_objects)[obj_idx]->volumes[volume_id]->name = m_objects_model->GetName(item).ToStdString();
+    (*m_objects)[obj_idx]->volumes[volume_id]->name = m_objects_model->GetName(item).ToUTF8().data();
 }
 
 void ObjectList::init_icons()
@@ -657,7 +657,7 @@ void ObjectList::append_menu_item_add_generic(wxMenuItem* menu, const int type)
     std::vector<std::string> menu_items = { L("Box"), L("Cylinder"), L("Sphere"), L("Slab") };
     for (auto& item : menu_items) {
         append_menu_item(sub_menu, wxID_ANY, _(item), "",
-            [this, type, item](wxCommandEvent&) { load_generic_subobject(_(item).ToStdString(), type); }, "", menu->GetMenu());
+            [this, type, item](wxCommandEvent&) { load_generic_subobject(_(item).ToUTF8().data(), type); }, "", menu->GetMenu());
     }
 
     menu->SetSubMenu(sub_menu);
@@ -683,10 +683,10 @@ void ObjectList::append_menu_items_add_volume(wxMenu* menu)
         append_menu_item(menu, wxID_ANY, _(L("Add part")), "",
             [this](wxCommandEvent&) { load_subobject(ModelVolume::MODEL_PART); }, *m_bmp_vector[ModelVolume::MODEL_PART]);
         append_menu_item(menu, wxID_ANY, _(L("Add support enforcer")), "",
-            [this](wxCommandEvent&) { load_generic_subobject(_(L("Box")).ToStdString(), ModelVolume::SUPPORT_ENFORCER); }, 
+            [this](wxCommandEvent&) { load_generic_subobject(_(L("Box")).ToUTF8().data(), ModelVolume::SUPPORT_ENFORCER); }, 
             *m_bmp_vector[ModelVolume::SUPPORT_ENFORCER]);
         append_menu_item(menu, wxID_ANY, _(L("Add support blocker")), "",
-            [this](wxCommandEvent&) { load_generic_subobject(_(L("Box")).ToStdString(), ModelVolume::SUPPORT_BLOCKER); }, 
+            [this](wxCommandEvent&) { load_generic_subobject(_(L("Box")).ToUTF8().data(), ModelVolume::SUPPORT_BLOCKER); }, 
             *m_bmp_vector[ModelVolume::SUPPORT_BLOCKER]);
 
         return;
@@ -823,7 +823,7 @@ void ObjectList::load_part( ModelObject* model_object,
     wxArrayString input_files;
     wxGetApp().import_model(parent, input_files);
     for (int i = 0; i < input_files.size(); ++i) {
-        std::string input_file = input_files.Item(i).ToStdString();
+        std::string input_file = input_files.Item(i).ToUTF8().data();
 
         Model model;
         try {
diff --git a/src/slic3r/GUI/GUI_ObjectManipulation.cpp b/src/slic3r/GUI/GUI_ObjectManipulation.cpp
index 32a38a77c..be421e5d3 100644
--- a/src/slic3r/GUI/GUI_ObjectManipulation.cpp
+++ b/src/slic3r/GUI/GUI_ObjectManipulation.cpp
@@ -438,7 +438,7 @@ void ObjectManipulation::change_scale_value(const Vec3d& scale)
             max_diff = abs_scale_diff(Z);
             max_diff_axis = Z;
         }
-        scaling_factor = Vec3d(scale(max_diff_axis), scale(max_diff_axis), scale(max_diff_axis));
+        scaling_factor = scale(max_diff_axis) * Vec3d::Ones();
     }
 
     scaling_factor *= 0.01;
@@ -464,10 +464,38 @@ void ObjectManipulation::change_size_value(const Vec3d& size)
         ref_size = volume->bounding_box.size();
     }
 
-    change_scale_value(100.0 * Vec3d(size(0) / ref_size(0), size(1) / ref_size(1), size(2) / ref_size(2)));
-
 #if ENABLE_IMPROVED_SIDEBAR_OBJECTS_MANIPULATION
+    Vec3d scale = 100.0 * Vec3d(size(0) / ref_size(0), size(1) / ref_size(1), size(2) / ref_size(2));
+    Vec3d scaling_factor = scale;
+
+    if (selection.requires_uniform_scale())
+    {
+        Vec3d abs_scale_diff = (scale - m_cache_scale).cwiseAbs();
+        double max_diff = abs_scale_diff(X);
+        Axis max_diff_axis = X;
+        if (max_diff < abs_scale_diff(Y))
+        {
+            max_diff = abs_scale_diff(Y);
+            max_diff_axis = Y;
+        }
+        if (max_diff < abs_scale_diff(Z))
+        {
+            max_diff = abs_scale_diff(Z);
+            max_diff_axis = Z;
+        }
+        scaling_factor = scale(max_diff_axis) * Vec3d::Ones();
+    }
+
+    scaling_factor *= 0.01;
+
+    auto canvas = wxGetApp().plater()->canvas3D();
+    canvas->get_selection().start_dragging();
+    canvas->get_selection().scale(scaling_factor, false);
+    canvas->do_scale();
+
     m_cache_size = size;
+#else
+    change_scale_value(100.0 * Vec3d(size(0) / ref_size(0), size(1) / ref_size(1), size(2) / ref_size(2)));
 #endif // ENABLE_IMPROVED_SIDEBAR_OBJECTS_MANIPULATION
 }
 
diff --git a/src/slic3r/GUI/MainFrame.cpp b/src/slic3r/GUI/MainFrame.cpp
index b4d779dfe..099dd4c50 100644
--- a/src/slic3r/GUI/MainFrame.cpp
+++ b/src/slic3r/GUI/MainFrame.cpp
@@ -490,7 +490,7 @@ void MainFrame::quick_slice(const int qs)
 //     });
 
     // keep model around
-    auto model = Slic3r::Model::read_from_file(input_file.ToStdString());
+    auto model = Slic3r::Model::read_from_file(input_file.ToUTF8().data());
 
 //     sprint->apply_config(config);
 //     sprint->set_model(model);
@@ -632,7 +632,7 @@ void MainFrame::export_config()
     if (!file.IsEmpty()) {
         wxGetApp().app_config->update_config_dir(get_dir_name(file));
         m_last_config = file;
-        config.save(file.ToStdString());
+        config.save(file.ToUTF8().data());
     }
 }
 
@@ -651,7 +651,7 @@ void MainFrame::load_config_file(wxString file/* = wxEmptyString*/)
         dlg->Destroy();
     }
     try {
-        wxGetApp().preset_bundle->load_config_file(file.ToStdString()); 
+        wxGetApp().preset_bundle->load_config_file(file.ToUTF8().data()); 
     } catch (const std::exception &ex) {
         show_error(this, ex.what());
         return;
@@ -684,7 +684,7 @@ void MainFrame::export_configbundle()
         // Export the config bundle.
         wxGetApp().app_config->update_config_dir(get_dir_name(file));
         try {
-            wxGetApp().preset_bundle->export_configbundle(file.ToStdString()); 
+            wxGetApp().preset_bundle->export_configbundle(file.ToUTF8().data()); 
         } catch (const std::exception &ex) {
 			show_error(this, ex.what());
         }
@@ -712,7 +712,7 @@ void MainFrame::load_configbundle(wxString file/* = wxEmptyString, const bool re
 
     auto presets_imported = 0;
     try {
-        presets_imported = wxGetApp().preset_bundle->load_configbundle(file.ToStdString());
+        presets_imported = wxGetApp().preset_bundle->load_configbundle(file.ToUTF8().data());
     } catch (const std::exception &ex) {
         show_error(this, ex.what());
         return;
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index c9440a9d0..941a181d3 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -2083,7 +2083,7 @@ void Plater::priv::on_select_preset(wxCommandEvent &evt)
     //! So, to get selected string we do 
     //!     combo->GetString(combo->GetSelection()) 
     //! instead of 
-    //!     combo->GetStringSelection().ToStdString()); 
+    //!     combo->GetStringSelection().ToUTF8().data()); 
 
     std::string selected_string = combo->GetString(combo->GetSelection()).ToUTF8().data();
 
@@ -2628,7 +2628,7 @@ void Plater::increase_instances(size_t num)
     float offset = 10.0;
     for (size_t i = 0; i < num; i++, offset += 10.0) {
         Vec3d offset_vec = model_instance->get_offset() + Vec3d(offset, offset, 0.0);
-        model_object->add_instance(offset_vec, model_instance->get_scaling_factor(), model_instance->get_rotation());
+        model_object->add_instance(offset_vec, model_instance->get_scaling_factor(), model_instance->get_rotation(), model_instance->get_mirror());
 //        p->print.get_object(obj_idx)->add_copy(Slic3r::to_2d(offset_vec));
     }
 
diff --git a/src/slic3r/GUI/PresetBundle.cpp b/src/slic3r/GUI/PresetBundle.cpp
index ee7ba279f..274f2a7ef 100644
--- a/src/slic3r/GUI/PresetBundle.cpp
+++ b/src/slic3r/GUI/PresetBundle.cpp
@@ -1164,6 +1164,22 @@ size_t PresetBundle::load_configbundle(const std::string &path, unsigned int fla
                         section.first << "\" has already been loaded from another Confing Bundle.";
                     continue;
                 }
+            } else if ((flags & LOAD_CFGBNDLE_SYSTEM) == 0) {
+                // This is a user config bundle.
+                const Preset *existing = presets->find_preset(preset_name, false);
+                if (existing != nullptr) {
+                    if (existing->is_system) {
+    					assert(existing->vendor != nullptr);
+                        BOOST_LOG_TRIVIAL(error) << "Error in a user provided Config Bundle \"" << path << "\": The " << presets->name() << " preset \"" << 
+    						existing->name << "\" is a system preset of vendor " << existing->vendor->name << " and it will be ignored.";
+                        continue;
+                    } else {
+                        assert(existing->vendor == nullptr);
+                        BOOST_LOG_TRIVIAL(trace) << "A " << presets->name() << " preset \"" << existing->name << "\" was overwritten with a preset from user Config Bundle \"" << path << "\"";
+                    }
+                } else {
+					BOOST_LOG_TRIVIAL(trace) << "A new " << presets->name() << " preset \"" << preset_name << "\" was imported from user Config Bundle \"" << path << "\"";
+                }
             }
             // Decide a full path to this .ini file.
             auto file_name = boost::algorithm::iends_with(preset_name, ".ini") ? preset_name : preset_name + ".ini";
diff --git a/src/slic3r/GUI/Tab.cpp b/src/slic3r/GUI/Tab.cpp
index 70751fd5d..83f7e1e73 100644
--- a/src/slic3r/GUI/Tab.cpp
+++ b/src/slic3r/GUI/Tab.cpp
@@ -209,7 +209,7 @@ void Tab::create_preset_tab()
 	m_presets_choice->Bind(wxEVT_COMBOBOX, ([this](wxCommandEvent e) {
 		//! Because of The MSW and GTK version of wxBitmapComboBox derived from wxComboBox, 
 		//! but the OSX version derived from wxOwnerDrawnCombo, instead of:
-		//! select_preset(m_presets_choice->GetStringSelection().ToStdString()); 
+		//! select_preset(m_presets_choice->GetStringSelection().ToUTF8().data()); 
 		//! we doing next:
 		int selected_item = m_presets_choice->GetSelection();
 		if (m_selected_preset_item == selected_item && !m_presets->current_is_dirty())
@@ -2889,7 +2889,7 @@ wxSizer* Tab::compatible_widget_create(wxWindow* parent, PresetDependencies &dep
 			selections.Clear();
 			selections = dlg.GetSelections();
 			for (auto idx : selections)
-				value.push_back(presets[idx].ToStdString());
+				value.push_back(presets[idx].ToUTF8().data());
 			if (value.empty()) {
 				deps.checkbox->SetValue(1);
 				deps.btn->Disable();
diff --git a/src/slic3r/GUI/wxExtensions.cpp b/src/slic3r/GUI/wxExtensions.cpp
index 6ea47b45b..466580074 100644
--- a/src/slic3r/GUI/wxExtensions.cpp
+++ b/src/slic3r/GUI/wxExtensions.cpp
@@ -422,13 +422,13 @@ bool PrusaObjectDataViewModelNode::update_settings_digest(const std::vector<std:
     if (!m_name.IsEmpty())
         m_name.erase(m_name.Length()-2, 2); // Delete last "; "
 
-    wxBitmap *bmp = m_bitmap_cache->find(m_name.ToStdString());
+    wxBitmap *bmp = m_bitmap_cache->find(m_name.ToUTF8().data());
     if (bmp == nullptr) {
         std::vector<wxBitmap> bmps;
         for (auto& cat : m_opt_categories)
             bmps.emplace_back(categories_icon.find(cat) == categories_icon.end() ?
                               wxNullBitmap : categories_icon.at(cat));
-        bmp = m_bitmap_cache->insert(m_name.ToStdString(), bmps);
+        bmp = m_bitmap_cache->insert(m_name.ToUTF8().data(), bmps);
     }
 
     m_bmp = *bmp;
diff --git a/src/slic3r/Utils/Duet.cpp b/src/slic3r/Utils/Duet.cpp
index 3449e610e..77137a7d2 100644
--- a/src/slic3r/Utils/Duet.cpp
+++ b/src/slic3r/Utils/Duet.cpp
@@ -75,6 +75,19 @@ bool Duet::upload(PrintHostUpload upload_data, ProgressFn prorgess_fn, ErrorFn e
 	http.set_post_body(upload_data.source_path)
 		.on_complete([&](std::string body, unsigned status) {
 			BOOST_LOG_TRIVIAL(debug) << boost::format("Duet: File uploaded: HTTP %1%: %2%") % status % body;
+
+			int err_code = get_err_code_from_body(body);
+			if (err_code != 0) {
+				BOOST_LOG_TRIVIAL(error) << boost::format("Duet: Request completed but error code was received: %1%") % err_code;
+				error_fn(format_error(body, L("Unknown error occured"), 0));
+				res = false;
+			} else if (upload_data.start_print) {
+				wxString errormsg;
+				res = start_print(errormsg, upload_data.upload_path.string());
+				if (! res) {
+					error_fn(std::move(errormsg));
+				}
+			}
 		})
 		.on_error([&](std::string body, std::string error, unsigned status) {
 			BOOST_LOG_TRIVIAL(error) << boost::format("Duet: Error uploading file: %1%, HTTP %2%, body: `%3%`") % error % status % body;
diff --git a/src/slic3r_app_msvc.cpp b/src/slic3r_app_msvc.cpp
index 9823a325d..7cd97dfc3 100644
--- a/src/slic3r_app_msvc.cpp
+++ b/src/slic3r_app_msvc.cpp
@@ -181,10 +181,10 @@ extern "C" {
 }
 
 #ifdef SLIC3R_WRAPPER_NOCONSOLE
-int APIENTRY wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, wchar_t *lpCmdLine, int nCmdShow)
+int APIENTRY wWinMain(HINSTANCE /* hInstance */, HINSTANCE /* hPrevInstance */, PWSTR /* lpCmdLine */, int /* nCmdShow */)
 {
 	int 	  argc;
-	wchar_t **argv = CommandLineToArgvW(lpCmdLine, &argc);
+	wchar_t **argv = ::CommandLineToArgvW(::GetCommandLineW(), &argc);
 #else
 int wmain(int argc, wchar_t **argv)
 {
diff --git a/version.inc b/version.inc
index 4bb281767..c24762003 100644
--- a/version.inc
+++ b/version.inc
@@ -2,7 +2,7 @@
 # (the version numbers are generated by the build script from the git current label)
 
 set(SLIC3R_FORK_NAME "Slic3r++")
-set(SLIC3R_VERSION "1.42.0-alpha1")
+set(SLIC3R_VERSION "1.42.0-alpha2")
 set(SLIC3R_BUILD "${SLIC3R_VERSION}+UNKNOWN")
 set(SLIC3R_BUILD_ID "${SLIC3R_BUILD_ID}")
 set(SLIC3R_RC_VERSION "1,42,0,0")