Merge branch 'master' of https://github.com/prusa3d/PrusaSlicer into dev

15 files changed, 215 insertions, 126 deletions

diff --git a/src/libslic3r/AppConfig.cpp b/src/libslic3r/AppConfig.cpp
index ab636a03e..ec5ce3702 100644
--- a/src/libslic3r/AppConfig.cpp
+++ b/src/libslic3r/AppConfig.cpp
@@ -43,6 +43,10 @@ const std::string AppConfig::SECTION_MATERIALS = "sla_materials";
 void AppConfig::reset()
 {
     m_storage.clear();
+    m_vendors.clear();
+    m_dirty = false;
+    m_orig_version = Semver::invalid();
+    m_legacy_datadir = false;
     set_defaults();
 };
 
@@ -243,8 +247,10 @@ static bool verify_config_file_checksum(boost::nowide::ifstream &ifs)
 }
 #endif
 
-std::string AppConfig::load()
+std::string AppConfig::load(const std::string &path)
 {
+    this->reset();
+
     // 1) Read the complete config file into a boost::property_tree.
     namespace pt = boost::property_tree;
     pt::ptree tree;
@@ -252,11 +258,11 @@ std::string AppConfig::load()
     bool                    recovered = false;
 
     try {
-        ifs.open(AppConfig::loading_path());
+        ifs.open(path);
 #ifdef WIN32
         // Verify the checksum of the config file without taking just for debugging purpose.
         if (!verify_config_file_checksum(ifs))
-            BOOST_LOG_TRIVIAL(info) << "The configuration file " << AppConfig::loading_path() <<
+            BOOST_LOG_TRIVIAL(info) << "The configuration file " << path <<
             " has a wrong MD5 checksum or the checksum is missing. This may indicate a file corruption or a harmless user edit.";
 
         ifs.seekg(0, boost::nowide::ifstream::beg);
@@ -266,32 +272,32 @@ std::string AppConfig::load()
 #ifdef WIN32
         // The configuration file is corrupted, try replacing it with the backup configuration.
         ifs.close();
-        std::string backup_path = (boost::format("%1%.bak") % AppConfig::loading_path()).str();
+        std::string backup_path = (boost::format("%1%.bak") % path).str();
         if (boost::filesystem::exists(backup_path)) {
             // Compute checksum of the configuration backup file and try to load configuration from it when the checksum is correct.
             boost::nowide::ifstream backup_ifs(backup_path);
             if (!verify_config_file_checksum(backup_ifs)) {
-                BOOST_LOG_TRIVIAL(error) << format("Both \"%1%\" and \"%2%\" are corrupted. It isn't possible to restore configuration from the backup.", AppConfig::loading_path(), backup_path);
+                BOOST_LOG_TRIVIAL(error) << format("Both \"%1%\" and \"%2%\" are corrupted. It isn't possible to restore configuration from the backup.", path, backup_path);
                 backup_ifs.close();
                 boost::filesystem::remove(backup_path);
-            } else if (std::string error_message; copy_file(backup_path, AppConfig::loading_path(), error_message, false) != SUCCESS) {
-                BOOST_LOG_TRIVIAL(error) << format("Configuration file \"%1%\" is corrupted. Failed to restore from backup \"%2%\": %3%", AppConfig::loading_path(), backup_path, error_message);
+            } else if (std::string error_message; copy_file(backup_path, path, error_message, false) != SUCCESS) {
+                BOOST_LOG_TRIVIAL(error) << format("Configuration file \"%1%\" is corrupted. Failed to restore from backup \"%2%\": %3%", path, backup_path, error_message);
                 backup_ifs.close();
                 boost::filesystem::remove(backup_path);
             } else {
-                BOOST_LOG_TRIVIAL(info) << format("Configuration file \"%1%\" was corrupted. It has been succesfully restored from the backup \"%2%\".", AppConfig::loading_path(), backup_path);
+                BOOST_LOG_TRIVIAL(info) << format("Configuration file \"%1%\" was corrupted. It has been succesfully restored from the backup \"%2%\".", path, backup_path);
                 // Try parse configuration file after restore from backup.
                 try {
-                    ifs.open(AppConfig::loading_path());
+                    ifs.open(path);
                     pt::read_ini(ifs, tree);
                     recovered = true;
                 } catch (pt::ptree_error& ex) {
-                    BOOST_LOG_TRIVIAL(info) << format("Failed to parse configuration file \"%1%\" after it has been restored from backup: %2%", AppConfig::loading_path(), ex.what());
+                    BOOST_LOG_TRIVIAL(info) << format("Failed to parse configuration file \"%1%\" after it has been restored from backup: %2%", path, ex.what());
                 }
             }
         } else
 #endif // WIN32
-            BOOST_LOG_TRIVIAL(info) << format("Failed to parse configuration file \"%1%\": %2%", AppConfig::loading_path(), ex.what());
+            BOOST_LOG_TRIVIAL(info) << format("Failed to parse configuration file \"%1%\": %2%", path, ex.what());
         if (! recovered) {
             // Report the initial error of parsing PrusaSlicer.ini.
             // Error while parsing config file. We'll customize the error message and rethrow to be displayed.
@@ -367,6 +373,11 @@ std::string AppConfig::load()
     return "";
 }
 
+std::string AppConfig::load()
+{
+    return this->load(AppConfig::config_path());
+}
+
 void AppConfig::save()
 {
     {
diff --git a/src/libslic3r/AppConfig.hpp b/src/libslic3r/AppConfig.hpp
index 5d9f32ab7..418f3427b 100644
--- a/src/libslic3r/AppConfig.hpp
+++ b/src/libslic3r/AppConfig.hpp
@@ -22,10 +22,7 @@ public:
 	};
 
 	explicit AppConfig(EAppMode mode) :
-		m_dirty(false),
-		m_orig_version(Semver::invalid()),
-		m_mode(mode),
-		m_legacy_datadir(false)
+		m_mode(mode)
 	{
 		this->reset();
 	}
@@ -38,6 +35,8 @@ public:
 	// Load the slic3r.ini from a user profile directory (or a datadir, if configured).
 	// return error string or empty strinf
 	std::string         load();
+	// Load from an explicit path.
+	std::string         load(const std::string &path);
 	// Store the slic3r.ini into a user profile directory (or a datadir, if configured).
 	void 			   	save();
 
@@ -148,9 +147,6 @@ public:
 	// Does the config file exist?
 	bool 				exists();
 
-	void                set_loading_path(const std::string& path) { m_loading_path = path; }
-	std::string         loading_path() { return (m_loading_path.empty() ? config_path() : m_loading_path); }
-
     std::vector<std::string> get_recent_projects() const;
     void set_recent_projects(const std::vector<std::string>& recent_projects);
 
@@ -199,8 +195,6 @@ private:
 	Semver                                                      m_orig_version;
 	// Whether the existing version is before system profiles & configuration updating
 	bool                                                        m_legacy_datadir;
-
-	std::string                                                 m_loading_path;
 };
 
 } // namespace Slic3r
diff --git a/src/libslic3r/GCode/AvoidCrossingPerimeters.cpp b/src/libslic3r/GCode/AvoidCrossingPerimeters.cpp
index 48b9515f7..417322584 100644
--- a/src/libslic3r/GCode/AvoidCrossingPerimeters.cpp
+++ b/src/libslic3r/GCode/AvoidCrossingPerimeters.cpp
@@ -731,34 +731,50 @@ static bool need_wipe(const GCode          &gcodegen,
 }
 
 // Adds points around all vertices so that the offset affects only small sections around these vertices.
-static void resample_polygon(Polygon &polygon, double dist_from_vertex)
+static void resample_polygon(Polygon &polygon, double dist_from_vertex, double max_allowed_distance)
 {
     Points resampled_poly;
     resampled_poly.reserve(3 * polygon.size());
-    resampled_poly.emplace_back(polygon.first_point());
-    for (size_t pt_idx = 1; pt_idx < polygon.size(); ++pt_idx) {
-        const Point &p1          = polygon[pt_idx - 1];
-        const Point &p2          = polygon[pt_idx];
-        double       line_length = (p2 - p1).cast<double>().norm();
-        Vector       line_vec    = ((p2 - p1).cast<double>().normalized() * dist_from_vertex).cast<coord_t>();
-        if (line_length > 2 * dist_from_vertex) {
-            resampled_poly.emplace_back(p1 + line_vec);
-            resampled_poly.emplace_back(p2 - line_vec);
-        }
+    for (size_t pt_idx = 0; pt_idx < polygon.size(); ++pt_idx) {
         resampled_poly.emplace_back(polygon[pt_idx]);
+
+        const Point &p1          = polygon[pt_idx];
+        const Point &p2          = polygon[next_idx_modulo(pt_idx, polygon.size())];
+        const Vec2d  line_vec    = (p2 - p1).cast<double>();
+        double       line_length = line_vec.norm();
+        const Vector vertex_offset_vec = (line_vec.normalized() * dist_from_vertex).cast<coord_t>();
+        if (line_length > 2 * dist_from_vertex && vertex_offset_vec != Vector(0, 0)) {
+            resampled_poly.emplace_back(p1 + vertex_offset_vec);
+
+            const Vec2d  new_vertex_vec        = (p2 - p1 - 2 * vertex_offset_vec).cast<double>();
+            const double new_vertex_vec_length = new_vertex_vec.norm();
+            if (new_vertex_vec_length > max_allowed_distance) {
+                const Vec2d &prev_point  = resampled_poly.back().cast<double>();
+                const size_t parts_count = size_t(ceil(new_vertex_vec_length / max_allowed_distance));
+                for (size_t part_idx = 1; part_idx < parts_count; ++part_idx) {
+                    const double part_param = double(part_idx) / double(parts_count);
+                    const Vec2d  new_point  = prev_point + new_vertex_vec * part_param;
+                    resampled_poly.emplace_back(new_point.cast<coord_t>());
+                }
+            }
+
+            resampled_poly.emplace_back(p2 - vertex_offset_vec);
+        }
     }
     polygon.points = std::move(resampled_poly);
 }
 
-static void resample_expolygon(ExPolygon &ex_polygon, double dist_from_vertex)
+static void resample_expolygon(ExPolygon &ex_polygon, double dist_from_vertex, double max_allowed_distance)
 {
-    resample_polygon(ex_polygon.contour, dist_from_vertex);
-    for (Polygon &polygon : ex_polygon.holes) resample_polygon(polygon, dist_from_vertex);
+    resample_polygon(ex_polygon.contour, dist_from_vertex, max_allowed_distance);
+    for (Polygon &polygon : ex_polygon.holes)
+        resample_polygon(polygon, dist_from_vertex, max_allowed_distance);
 }
 
-static void resample_expolygons(ExPolygons &ex_polygons, double dist_from_vertex)
+static void resample_expolygons(ExPolygons &ex_polygons, double dist_from_vertex, double max_allowed_distance)
 {
-    for (ExPolygon &ex_poly : ex_polygons) resample_expolygon(ex_poly, dist_from_vertex);
+    for (ExPolygon &ex_poly : ex_polygons)
+        resample_expolygon(ex_poly, dist_from_vertex, max_allowed_distance);
 }
 
 static void precompute_polygon_distances(const Polygon &polygon, std::vector<float> &polygon_distances_out)
@@ -834,7 +850,7 @@ static std::vector<float> contour_distance(const EdgeGrid::Grid     &grid,
                             double                   param_end = boundary_parameters.back();
                             const size_t ipt = it_contour_and_segment->second;
                             if (contour.begin() + ipt + 1 < contour.end())
-                                param_hi += boundary_parameters[ipt > 0 ? ipt - 1 : 0];
+                                param_hi += boundary_parameters[ipt];
                             if (param_lo > param_hi)
                                 std::swap(param_lo, param_hi);
                             assert(param_lo > -SCALED_EPSILON && param_lo <= param_end + SCALED_EPSILON);
@@ -932,7 +948,7 @@ static ExPolygons inner_offset(const ExPolygons &ex_polygons, double offset)
     double     min_contour_width = 2. * offset + SCALED_EPSILON;
     double     search_radius     = 2. * (offset + min_contour_width);
     ExPolygons ex_poly_result    = ex_polygons;
-    resample_expolygons(ex_poly_result, offset / 2);
+    resample_expolygons(ex_poly_result, offset / 2, scaled<double>(0.5));
 
     for (ExPolygon &ex_poly : ex_poly_result) {
         BoundingBox bbox(get_extents(ex_poly));
@@ -1034,24 +1050,30 @@ static Polygons get_boundary_external(const Layer &layer)
 #endif
     // Collect all holes for all printed objects and their instances, which will be printed at the same time as passed "layer".
     for (const PrintObject *object : layer.object()->print()->objects()) {
-        Polygons   polygons_per_obj;
+        Polygons   holes_per_obj;
 #ifdef INCLUDE_SUPPORTS_IN_BOUNDARY
         ExPolygons supports_per_obj;
 #endif
         if (const Layer *l = object->get_layer_at_printz(layer.print_z, EPSILON); l)
-            for (const ExPolygon &island : l->lslices) append(polygons_per_obj, island.holes);
+            for (const ExPolygon &island : l->lslices)
+                append(holes_per_obj, island.holes);
         if (support_layer) {
             auto *layer_below = object->get_first_layer_bellow_printz(layer.print_z, EPSILON);
             if (layer_below)
-                for (const ExPolygon &island : layer_below->lslices) append(polygons_per_obj, island.holes);
+                for (const ExPolygon &island : layer_below->lslices)
+                    append(holes_per_obj, island.holes);
 #ifdef INCLUDE_SUPPORTS_IN_BOUNDARY
             append(supports_per_obj, support_layer->support_islands.expolygons);
 #endif
         }
 
+        // After 7ff76d07684858fd937ef2f5d863f105a10f798e, when expand is called on CW polygons (holes), they are shrunk
+        // instead of expanded because union that makes CCW from CW isn't called anymore. So let's make it CCW.
+        polygons_reverse(holes_per_obj);
+
         for (const PrintInstance &instance : object->instances()) {
             size_t boundary_idx = boundary.size();
-            append(boundary, polygons_per_obj);
+            append(boundary, holes_per_obj);
             for (; boundary_idx < boundary.size(); ++boundary_idx)
                 boundary[boundary_idx].translate(instance.shift);
 #ifdef INCLUDE_SUPPORTS_IN_BOUNDARY
diff --git a/src/libslic3r/Preset.cpp b/src/libslic3r/Preset.cpp
index 65027a390..2397a7d19 100644
--- a/src/libslic3r/Preset.cpp
+++ b/src/libslic3r/Preset.cpp
@@ -1391,7 +1391,7 @@ const Preset* PrinterPresetCollection::find_system_preset_by_model_and_variant(c
 bool  PrinterPresetCollection::only_default_printers() const
 {
     for (const auto& printer : get_presets()) {
-        if (!boost::starts_with(printer.name,"- default"))
+        if (! printer.is_default)
             return false;
     }
     return true;
diff --git a/src/libslic3r/PresetBundle.cpp b/src/libslic3r/PresetBundle.cpp
index b6e7fbd5e..874b775cd 100644
--- a/src/libslic3r/PresetBundle.cpp
+++ b/src/libslic3r/PresetBundle.cpp
@@ -209,18 +209,34 @@ static void copy_dir(const boost::filesystem::path& from_dir, const boost::files
     }
 }
 
-void PresetBundle::copy_files(const std::string& from)
+// Import newer configuration from alternate PrusaSlicer configuration directory.
+// AppConfig from the alternate location is already loaded.
+// User profiles are being merged (old files are not being deleted),
+// while old vendors and cache folders are being deleted before newer are copied.
+void PresetBundle::import_newer_configs(const std::string& from)
 {
     boost::filesystem::path data_dir = boost::filesystem::path(Slic3r::data_dir());
+    // Clean-up vendors from the target directory, as the existing vendors will not be referenced
+    // by the copied PrusaSlicer.ini
+    try {
+        boost::filesystem::remove_all(data_dir / "cache");
+    } catch (const std::exception &ex) {
+        BOOST_LOG_TRIVIAL(error) << "Error deleting old cache " << (data_dir / "cache").string() << ": " << ex.what();
+    }
+    try {
+        boost::filesystem::remove_all(data_dir / "vendor");
+    } catch (const std::exception &ex) {
+        BOOST_LOG_TRIVIAL(error) << "Error deleting old vendors " << (data_dir / "vendor").string() << ": " << ex.what();
+    }
     // list of searched paths based on current directory system in setup_directories()
     // do not copy cache and snapshots
     boost::filesystem::path from_data_dir = boost::filesystem::path(from);
     std::initializer_list<boost::filesystem::path> from_dirs= {
+        from_data_dir / "cache",
         from_data_dir / "vendor",
         from_data_dir / "shapes",
 #ifdef SLIC3R_PROFILE_USE_PRESETS_SUBDIR
         // Store the print/filament/printer presets into a "presets" directory.
-        data_dir / "presets",
         data_dir / "presets" / "print",
         data_dir / "presets" / "filament",
         data_dir / "presets" / "sla_print",
@@ -1235,11 +1251,13 @@ std::pair<PresetsConfigSubstitutions, size_t> PresetBundle::load_configbundle(
     // 1) Read the complete config file into a boost::property_tree.
     namespace pt = boost::property_tree;
     pt::ptree tree;
-    boost::nowide::ifstream ifs(path);
-    try {
-        pt::read_ini(ifs, tree);
-    } catch (const boost::property_tree::ini_parser::ini_parser_error &err) {
-        throw Slic3r::RuntimeError(format("Failed loading config bundle \"%1%\"\nError: \"%2%\" at line %3%", path, err.message(), err.line()).c_str());
+    {
+        boost::nowide::ifstream ifs(path);
+        try {
+            pt::read_ini(ifs, tree);
+        } catch (const boost::property_tree::ini_parser::ini_parser_error &err) {
+            throw Slic3r::RuntimeError(format("Failed loading config bundle \"%1%\"\nError: \"%2%\" at line %3%", path, err.message(), err.line()).c_str());
+        }
     }
 
     const VendorProfile *vendor_profile = nullptr;
diff --git a/src/libslic3r/PresetBundle.hpp b/src/libslic3r/PresetBundle.hpp
index a975e37fe..2a5ce6839 100644
--- a/src/libslic3r/PresetBundle.hpp
+++ b/src/libslic3r/PresetBundle.hpp
@@ -24,7 +24,7 @@ public:
     void            reset(bool delete_files);
 
     void            setup_directories();
-    void            copy_files(const std::string& from);
+    void            import_newer_configs(const std::string& from);
 
     struct PresetPreferences {
         std::string printer_model_id;// name of a preferred printer model
diff --git a/src/slic3r/Config/Snapshot.cpp b/src/slic3r/Config/Snapshot.cpp
index 77a74bffe..a0f386339 100644
--- a/src/slic3r/Config/Snapshot.cpp
+++ b/src/slic3r/Config/Snapshot.cpp
@@ -586,10 +586,12 @@ const Snapshot* take_config_snapshot_report_error(const AppConfig &app_config, S
     }
 }
 
-bool take_config_snapshot_cancel_on_error(const AppConfig &app_config, Snapshot::Reason reason, const std::string &comment, const std::string &message)
+bool take_config_snapshot_cancel_on_error(const AppConfig &app_config, Snapshot::Reason reason, const std::string &comment, const std::string &message, Snapshot const **psnapshot)
 {
     try {
-        SnapshotDB::singleton().take_snapshot(app_config, reason, comment);
+        const Snapshot *snapshot = &SnapshotDB::singleton().take_snapshot(app_config, reason, comment);
+        if (psnapshot)
+            *psnapshot = snapshot;
         return true;
     } catch (std::exception &err) {
         RichMessageDialog dlg(static_cast<wxWindow*>(wxGetApp().mainframe),
diff --git a/src/slic3r/Config/Snapshot.hpp b/src/slic3r/Config/Snapshot.hpp
index f45300633..5793aa548 100644
--- a/src/slic3r/Config/Snapshot.hpp
+++ b/src/slic3r/Config/Snapshot.hpp
@@ -132,7 +132,7 @@ const Snapshot* take_config_snapshot_report_error(const AppConfig &app_config, S
 
 // Take snapshot on SnapshotDB::singleton(). If taking snapshot fails, report "message", and present a "Continue" or "Abort" buttons to respond.
 // Return true on success and on "Continue" to continue with the process (for example installation of presets).
-bool take_config_snapshot_cancel_on_error(const AppConfig &app_config, Snapshot::Reason reason, const std::string &comment, const std::string &message);
+bool take_config_snapshot_cancel_on_error(const AppConfig &app_config, Snapshot::Reason reason, const std::string &comment, const std::string &message, Snapshot const **psnapshot = nullptr);
 
 } // namespace Config
 } // namespace GUI
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 622f5b3e2..a3b54a841 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -1869,6 +1869,12 @@ void GLCanvas3D::reload_scene(bool refresh_immediately, bool force_full_scene_re
                 // updates volumes transformations
                 volume->set_instance_transformation(mvs->model_volume->get_object()->instances[mvs->composite_id.instance_id]->get_transformation());
                 volume->set_volume_transformation(mvs->model_volume->get_transformation());
+
+                // updates volumes convex hull
+                if (mvs->model_volume->is_model_part() && ! volume->convex_hull())
+                    // Model volume was likely changed from modifier or support blocker / enforcer to a model part.
+                    // Only model parts require convex hulls.
+                    volume->set_convex_hull(mvs->model_volume->get_convex_hull_shared_ptr());
             }
         }
     }
diff --git a/src/slic3r/GUI/GUI_App.cpp b/src/slic3r/GUI/GUI_App.cpp
index e4078c9c1..cf14fc735 100644
--- a/src/slic3r/GUI/GUI_App.cpp
+++ b/src/slic3r/GUI/GUI_App.cpp
@@ -862,9 +862,9 @@ static boost::optional<Semver> parse_semver_from_ini(std::string path)
 void GUI_App::init_app_config()
 {
 	// Profiles for the alpha are stored into the PrusaSlicer-alpha directory to not mix with the current release.
-//    SetAppName(SLIC3R_APP_KEY);
+    SetAppName(SLIC3R_APP_KEY);
 //	SetAppName(SLIC3R_APP_KEY "-alpha");
-    SetAppName(SLIC3R_APP_KEY "-beta");
+//    SetAppName(SLIC3R_APP_KEY "-beta");
 //	SetAppDisplayName(SLIC3R_APP_NAME);
 
 	// Set the Slic3r data directory at the Slic3r XS module.
@@ -909,17 +909,18 @@ void GUI_App::init_app_config()
                     "\n\n" + app_config->config_path() + "\n\n" + error);
             }
         }
-        // Save orig_version here, so its empty if no app_config existed before this run.
-        m_last_config_version = app_config->orig_version();//parse_semver_from_ini(app_config->config_path());
     }
 }
 
-// returns true if found newer version and user agreed to use it
-bool GUI_App::check_older_app_config(Semver current_version, bool backup)
+// returns old config path to copy from if such exists,
+// returns an empty string if such config path does not exists or if it cannot be loaded.
+std::string GUI_App::check_older_app_config(Semver current_version, bool backup)
 {
+    std::string older_data_dir_path;
+
     // If the config folder is redefined - do not check
     if (m_datadir_redefined)
-        return false;
+        return {};
 
     // find other version app config (alpha / beta / release)
     std::string             config_path = app_config->config_path();
@@ -940,13 +941,13 @@ bool GUI_App::check_older_app_config(Semver current_version, bool backup)
             boost::optional<Semver>other_semver = parse_semver_from_ini(candidate.string());
             if (other_semver && *other_semver > last_semver) {
                 last_semver = *other_semver;
-                m_older_data_dir_path = candidate.parent_path().string();
+                older_data_dir_path = candidate.parent_path().string();
             }
         }
     }
-    if (m_older_data_dir_path.empty())
-        return false;
-    BOOST_LOG_TRIVIAL(info) << "last app config file used: " << m_older_data_dir_path;
+    if (older_data_dir_path.empty())
+        return {};
+    BOOST_LOG_TRIVIAL(info) << "last app config file used: " << older_data_dir_path;
     // ask about using older data folder
 
     InfoDialog msg(nullptr
@@ -959,13 +960,13 @@ bool GUI_App::check_older_app_config(Semver current_version, bool backup)
             "\n\nShall the newer configuration be imported?"
             "\nIf so, your active configuration will be backed up before importing the new configuration."
         )
-            , SLIC3R_APP_NAME, current_version.to_string(), m_older_data_dir_path, last_semver.to_string())
+            , SLIC3R_APP_NAME, current_version.to_string(), older_data_dir_path, last_semver.to_string())
         : format_wxstr(_L(
             "An existing configuration was found in <b>%3%</b>"
             "\ncreated by <b>%1% %2%</b>."
             "\n\nShall this configuration be imported?"
         )
-            , SLIC3R_APP_NAME, last_semver.to_string(), m_older_data_dir_path)
+            , SLIC3R_APP_NAME, last_semver.to_string(), older_data_dir_path)
         , true, wxYES_NO);
 
     if (backup) {
@@ -976,24 +977,21 @@ bool GUI_App::check_older_app_config(Semver current_version, bool backup)
     if (msg.ShowModal() == wxID_YES) {
         std::string snapshot_id;
         if (backup) {
-            // configuration snapshot
-            std::string comment;
-            if (const Config::Snapshot* snapshot = Config::take_config_snapshot_report_error(
-                    *app_config, 
-                    Config::Snapshot::SNAPSHOT_USER, 
-                    comment);
-                    snapshot != nullptr)
-                // Is thos correct? Save snapshot id for later, when new app config is loaded.
+            const Config::Snapshot* snapshot{ nullptr };
+            if (! GUI::Config::take_config_snapshot_cancel_on_error(*app_config, Config::Snapshot::SNAPSHOT_USER, "",
+                _u8L("Continue and import newer configuration?"), &snapshot))
+                return {};
+            if (snapshot) {
+                // Save snapshot ID before loading the alternate AppConfig, as loading the alternate AppConfig may fail.
                 snapshot_id = snapshot->id;
-            else
-                BOOST_LOG_TRIVIAL(error) << "Failed to take congiguration snapshot: ";
+                assert(! snapshot_id.empty());
+                app_config->set("on_snapshot", snapshot_id);
+            } else
+                BOOST_LOG_TRIVIAL(error) << "Failed to take congiguration snapshot";
         }
 
-        // This will tell later (when config folder structure is sure to exists) to copy files from m_older_data_dir_path
-        m_init_app_config_from_older = true;
         // load app config from older file
-        app_config->set_loading_path((boost::filesystem::path(m_older_data_dir_path) / filename).string());
-        std::string error = app_config->load();
+        std::string error = app_config->load((boost::filesystem::path(older_data_dir_path) / filename).string());
         if (!error.empty()) {
             // Error while parsing config file. We'll customize the error message and rethrow to be displayed.
             if (is_editor()) {
@@ -1012,14 +1010,9 @@ bool GUI_App::check_older_app_config(Semver current_version, bool backup)
         if (!snapshot_id.empty())
             app_config->set("on_snapshot", snapshot_id);
         m_app_conf_exists = true;
-        return true;
+        return older_data_dir_path;
     }
-    return false;
-}
-
-void GUI_App::copy_older_config()
-{
-    preset_bundle->copy_files(m_older_data_dir_path);
+    return {};
 }
 
 void GUI_App::init_single_instance_checker(const std::string &name, const std::string &path)
@@ -1085,6 +1078,42 @@ bool GUI_App::on_init_inner()
 
 //     Slic3r::debugf "wxWidgets version %s, Wx version %s\n", wxVERSION_STRING, wxVERSION;
 
+    // !!! Initialization of UI settings as a language, application color mode, fonts... have to be done before first UI action.
+    // Like here, before the show InfoDialog in check_older_app_config()
+
+    // If load_language() fails, the application closes.
+    load_language(wxString(), true);
+#ifdef _MSW_DARK_MODE
+    bool init_dark_color_mode = app_config->get("dark_color_mode") == "1";
+    bool init_sys_menu_enabled = app_config->get("sys_menu_enabled") == "1";
+    NppDarkMode::InitDarkMode(init_dark_color_mode, init_sys_menu_enabled);
+#endif
+    // initialize label colors and fonts
+    init_label_colours();
+    init_fonts();
+
+    std::string older_data_dir_path;
+    if (m_app_conf_exists) {
+        if (app_config->orig_version().valid() && app_config->orig_version() < *Semver::parse(SLIC3R_VERSION))
+            // Only copying configuration if it was saved with a newer slicer than the one currently running.
+            older_data_dir_path = check_older_app_config(app_config->orig_version(), true);
+    } else {
+        // No AppConfig exists, fresh install. Always try to copy from an alternate location, don't make backup of the current configuration.
+        older_data_dir_path = check_older_app_config(Semver(), false);
+    }
+
+#ifdef _MSW_DARK_MODE
+    // app_config can be updated in check_older_app_config(), so check if dark_color_mode and sys_menu_enabled was changed
+    if (bool new_dark_color_mode = app_config->get("dark_color_mode") == "1";
+        init_dark_color_mode != new_dark_color_mode) {
+        NppDarkMode::SetDarkMode(new_dark_color_mode);
+        init_label_colours();
+        update_label_colours_from_appconfig();
+    }
+    if (bool new_sys_menu_enabled = app_config->get("sys_menu_enabled") == "1";
+        init_sys_menu_enabled != new_sys_menu_enabled)
+        NppDarkMode::SetSystemMenuForApp(new_sys_menu_enabled);
+#endif
 
     if (is_editor()) {
         std::string msg = Http::tls_global_init();
@@ -1106,24 +1135,6 @@ bool GUI_App::on_init_inner()
         }
     }
 
-    // Set language and color mode before check_older_app_config() call
-
-    // If load_language() fails, the application closes.
-    load_language(wxString(), true);
-#ifdef _MSW_DARK_MODE
-    NppDarkMode::InitDarkMode(app_config->get("dark_color_mode") == "1", app_config->get("sys_menu_enabled") == "1");
-#endif
-
-    if (m_last_config_version) {
-        if (*m_last_config_version < *Semver::parse(SLIC3R_VERSION))
-            check_older_app_config(*m_last_config_version, true);
-    } else {
-        check_older_app_config(Semver(), false);
-    }
-
-    app_config->set("version", SLIC3R_VERSION);
-    app_config->save();
-
     SplashScreen* scrn = nullptr;
     if (app_config->get("show_splash_screen") == "1") {
         // make a bitmap with dark grey banner on the left side
@@ -1152,10 +1163,13 @@ bool GUI_App::on_init_inner()
     // just checking for existence of Slic3r::data_dir is not enough : it may be an empty directory
     // supplied as argument to --datadir; in that case we should still run the wizard
     preset_bundle->setup_directories();
-
     
-    if (m_init_app_config_from_older)
-        copy_older_config();
+    if (! older_data_dir_path.empty())
+        preset_bundle->import_newer_configs(older_data_dir_path);
+
+    // Save PrusaSlicer.ini after possibly copying the config from the alternate location and after all the configs from the alternate location were copied.
+    app_config->set("version", SLIC3R_VERSION);
+    app_config->save();
 
     if (is_editor()) {
 #ifdef __WXMSW__ 
@@ -1204,10 +1218,6 @@ bool GUI_App::on_init_inner()
 #endif // __WXMSW__
     }
 
-    // initialize label colors and fonts
-    init_label_colours();
-    init_fonts();
-
     // Suppress the '- default -' presets.
     preset_bundle->set_default_suppressed(app_config->get("no_defaults") == "1");
     try {
@@ -1708,6 +1718,7 @@ void GUI_App::force_colors_update()
     if (WXHWND wxHWND = wxToolTip::GetToolTipCtrl())
         NppDarkMode::SetDarkExplorerTheme((HWND)wxHWND);
     NppDarkMode::SetDarkTitleBar(mainframe->GetHWND());
+    NppDarkMode::SetDarkTitleBar(mainframe->m_settings_dialog.GetHWND());
 #endif //_MSW_DARK_MODE
     m_force_colors_update = true;
 }
@@ -1727,6 +1738,14 @@ void GUI_App::update_ui_from_settings()
         mainframe->printhost_queue_dlg()->force_color_changed();
 #ifdef _MSW_DARK_MODE
         update_scrolls(mainframe);
+        if (mainframe->is_dlg_layout()) {
+            // update for tabs bar
+            UpdateDarkUI(&mainframe->m_settings_dialog);
+            mainframe->m_settings_dialog.Fit();
+            mainframe->m_settings_dialog.Refresh();
+            // update scrollbars
+            update_scrolls(&mainframe->m_settings_dialog);
+        }
 #endif //_MSW_DARK_MODE
     }
 #endif
diff --git a/src/slic3r/GUI/GUI_App.hpp b/src/slic3r/GUI/GUI_App.hpp
index b1b0a7786..9c65bc024 100644
--- a/src/slic3r/GUI/GUI_App.hpp
+++ b/src/slic3r/GUI/GUI_App.hpp
@@ -341,8 +341,9 @@ public:
 private:
     bool            on_init_inner();
 	void            init_app_config();
-    bool            check_older_app_config(Semver current_version, bool backup);
-    void            copy_older_config();
+    // returns old config path to copy from if such exists,
+    // returns an empty string if such config path does not exists or if it cannot be loaded.
+    std::string     check_older_app_config(Semver current_version, bool backup);
     void            window_pos_save(wxTopLevelWindow* window, const std::string &name);
     void            window_pos_restore(wxTopLevelWindow* window, const std::string &name, bool default_maximized = false);
     void            window_pos_sanitize(wxTopLevelWindow* window);
@@ -351,10 +352,7 @@ private:
     bool            config_wizard_startup();
 	void            check_updates(const bool verbose);
 
-    bool                    m_init_app_config_from_older { false };
-    bool                    m_datadir_redefined { false }; 
-    std::string             m_older_data_dir_path;
-    boost::optional<Semver> m_last_config_version;
+    bool            m_datadir_redefined { false }; 
 };
 
 DECLARE_APP(GUI_App)
diff --git a/src/slic3r/GUI/GUI_ObjectList.cpp b/src/slic3r/GUI/GUI_ObjectList.cpp
index 160999db3..85ab42119 100644
--- a/src/slic3r/GUI/GUI_ObjectList.cpp
+++ b/src/slic3r/GUI/GUI_ObjectList.cpp
@@ -1398,6 +1398,8 @@ void ObjectList::load_subobject(ModelVolumeType type, bool from_galery/* = false
     if (m_objects_model->GetItemType(item)&itInstance)
         item = m_objects_model->GetItemById(obj_idx);
 
+    take_snapshot((type == ModelVolumeType::MODEL_PART) ? _L("Load Part") : _L("Load Modifier"));
+
     std::vector<ModelVolume*> volumes;
     // ! ysFIXME - delete commented code after testing and rename "load_modifier" to something common
     /*
@@ -1409,8 +1411,6 @@ void ObjectList::load_subobject(ModelVolumeType type, bool from_galery/* = false
     if (volumes.empty())
         return;
 
-    take_snapshot((type == ModelVolumeType::MODEL_PART) ? _L("Load Part") : _L("Load Modifier"));
-
     wxDataViewItemArray items = reorder_volumes_and_get_selection(obj_idx, [volumes](const ModelVolume* volume) {
         return std::find(volumes.begin(), volumes.end(), volume) != volumes.end(); });
 
diff --git a/src/slic3r/GUI/MsgDialog.cpp b/src/slic3r/GUI/MsgDialog.cpp
index 4e2462d4b..a70a9b172 100644
--- a/src/slic3r/GUI/MsgDialog.cpp
+++ b/src/slic3r/GUI/MsgDialog.cpp
@@ -131,7 +131,11 @@ static void add_msg_content(wxWindow* parent, wxBoxSizer* content_sizer, wxStrin
 
     wxFont      font = wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT);
     wxFont      monospace = wxGetApp().code_font();
+#ifdef _WIN32
     wxColour    text_clr = wxGetApp().get_label_clr_default();
+#else
+    wxColour    text_clr = wxSystemSettings::GetColour(wxSYS_COLOUR_WINDOWTEXT);
+#endif
     wxColour    bgr_clr = parent->GetBackgroundColour(); //wxSystemSettings::GetColour(wxSYS_COLOUR_WINDOW);
     auto        text_clr_str = wxString::Format(wxT("#%02X%02X%02X"), text_clr.Red(), text_clr.Green(), text_clr.Blue());
     auto        bgr_clr_str = wxString::Format(wxT("#%02X%02X%02X"), bgr_clr.Red(), bgr_clr.Green(), bgr_clr.Blue());
@@ -143,6 +147,20 @@ static void add_msg_content(wxWindow* parent, wxBoxSizer* content_sizer, wxStrin
     // calculate html page size from text
     wxSize page_size;
     int em = wxGetApp().em_unit();
+    if (!wxGetApp().mainframe) {
+        // If mainframe is nullptr, it means that GUI_App::on_init_inner() isn't completed 
+        // (We just show information dialog about configuration version now)
+        // And as a result the em_unit value wasn't created yet
+        // So, calculate it from the scale factor of Dialog
+#if defined(__WXGTK__)
+        // Linux specific issue : get_dpi_for_window(this) still doesn't responce to the Display's scale in new wxWidgets(3.1.3).
+        // So, initialize default width_unit according to the width of the one symbol ("m") of the currently active font of this window.
+        em = std::max<size_t>(10, parent->GetTextExtent("m").x - 1);
+#else
+        double scale_factor = (double)get_dpi_for_window(parent) / (double)DPI_DEFAULT;
+        em = std::max<size_t>(10, 10.0f * scale_factor);
+#endif // __WXGTK__
+    }
 
     // if message containes the table
     if (msg.Contains("<tr>")) {
diff --git a/src/slic3r/GUI/Tab.cpp b/src/slic3r/GUI/Tab.cpp
index 417ab60fa..2f2db22a7 100644
--- a/src/slic3r/GUI/Tab.cpp
+++ b/src/slic3r/GUI/Tab.cpp
@@ -1769,14 +1769,13 @@ void TabPrint::update()
     // Note: This workaround works till "support_material" and "overhangs" is exclusive sets of mutually no-exclusive parameters.
     // But it should be corrected when we will have more such sets.
     // Disable check of the compatibility of the "support_material" and "overhangs" options for saved user profile
-    // or for profile which was loaded from 3mf
-//    if (!m_config_manipulation.is_initialized_support_material_overhangs_queried())
-    if (bool support_material_overhangs_queried = m_config->opt_bool("support_material") && !m_config->opt_bool("overhangs"))
+    // NOTE: Initialization of the support_material_overhangs_queried value have to be processed just ones
+    if (!m_config_manipulation.is_initialized_support_material_overhangs_queried())
     {
         const Preset& selected_preset = m_preset_bundle->prints.get_selected_preset();
         bool is_user_and_saved_preset = !selected_preset.is_system && !selected_preset.is_dirty;
-        bool is_saved_in_3mf_preset = selected_preset.is_dirty && !wxGetApp().plater()->is_presets_dirty();
-        m_config_manipulation.initialize_support_material_overhangs_queried((is_user_and_saved_preset || is_saved_in_3mf_preset) && support_material_overhangs_queried);
+        bool support_material_overhangs_queried = m_config->opt_bool("support_material") && !m_config->opt_bool("overhangs");
+        m_config_manipulation.initialize_support_material_overhangs_queried(is_user_and_saved_preset && support_material_overhangs_queried);
     }
 
     m_config_manipulation.update_print_fff_config(m_config, true);
diff --git a/src/slic3r/GUI/UpdateDialogs.cpp b/src/slic3r/GUI/UpdateDialogs.cpp
index 367c290d9..f80975ce5 100644
--- a/src/slic3r/GUI/UpdateDialogs.cpp
+++ b/src/slic3r/GUI/UpdateDialogs.cpp
@@ -132,6 +132,7 @@ MsgUpdateConfig::MsgUpdateConfig(const std::vector<Update> &updates, bool force_
 			line->AddSpacer(3*VERT_SPACING);
 			line->Add(new wxHyperlinkCtrl(this, wxID_ANY, _(L("Open changelog page")), changelog_url));
 			versions->Add(line);
+			versions->AddSpacer(1); // empty value for the correct alignment inside a GridSizer
 		}
 	}
 
@@ -189,6 +190,7 @@ MsgUpdateForced::MsgUpdateForced(const std::vector<Update>& updates) :
 			line->AddSpacer(3 * VERT_SPACING);
 			line->Add(new wxHyperlinkCtrl(this, wxID_ANY, _(L("Open changelog page")), changelog_url));
 			versions->Add(line);
+			versions->AddSpacer(1); // empty value for the correct alignment inside a GridSizer
 		}
 	}