diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index ec9392ec4..4d3ad00dd 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -717,6 +717,7 @@ void GCode::_do_export(Print &print, FILE *file)
     // Prepare the helper object for replacing placeholders in custom G-code and output filename.
     m_placeholder_parser = print.placeholder_parser();
     m_placeholder_parser.update_timestamp();
+    print.update_object_placeholders(m_placeholder_parser.config_writable());
 
     // Get optimal tool ordering to minimize tool switches of a multi-exruder print.
     // For a print by objects, find the 1st printing object.
diff --git a/src/libslic3r/GCode/CoolingBuffer.cpp b/src/libslic3r/GCode/CoolingBuffer.cpp
index 09d211994..552fbf88c 100644
--- a/src/libslic3r/GCode/CoolingBuffer.cpp
+++ b/src/libslic3r/GCode/CoolingBuffer.cpp
@@ -252,8 +252,10 @@ float new_feedrate_to_reach_time_stretch(
 			for (size_t i = 0; i < (*it)->n_lines_adjustable; ++i) {
 				const CoolingLine &line = (*it)->lines[i];
                 if (line.feedrate > min_feedrate && line.feedrate < new_feedrate)
-                    // Some of the line segments taken into account in the calculation of nomin / denom are now slower than new_feedrate.
-                    // Re-run the calculation with a new min_feedrate limit.
+                    // Some of the line segments taken into account in the calculation of nomin / denom are now slower than new_feedrate, 
+                    // which makes the new_feedrate lower than it should be.
+                    // Re-run the calculation with a new min_feedrate limit, so that the segments with current feedrate lower than new_feedrate
+                    // are not taken into account.
                     goto not_finished_yet;
             }
         goto finished;
diff --git a/src/libslic3r/Model.cpp b/src/libslic3r/Model.cpp
index 968a3e234..08eb8df81 100644
--- a/src/libslic3r/Model.cpp
+++ b/src/libslic3r/Model.cpp
@@ -547,13 +547,26 @@ void Model::reset_auto_extruder_id()
     s_auto_extruder_id = 1;
 }
 
-std::string Model::propose_export_file_name() const
+// Propose a filename including path derived from the ModelObject's input path.
+// If object's name is filled in, use the object name, otherwise use the input name.
+std::string Model::propose_export_file_name_and_path() const
 {
     std::string input_file;
     for (const ModelObject *model_object : this->objects)
         for (ModelInstance *model_instance : model_object->instances)
             if (model_instance->is_printable()) {
-                input_file = model_object->name.empty() ? model_object->input_file : model_object->name;
+                input_file = model_object->input_file;
+                if (! model_object->name.empty()) {
+                    if (input_file.empty())
+                        // model_object->input_file was empty, just use model_object->name
+                        input_file = model_object->name;
+                    else {
+                        // Replace file name in input_file with model_object->name, but keep the path and file extension.
+						input_file = (boost::filesystem::path(model_object->name).parent_path().empty()) ?
+							(boost::filesystem::path(input_file).parent_path() / model_object->name).make_preferred().string() :
+							model_object->name;
+					}
+                }
                 if (! input_file.empty())
                     goto end;
                 // Other instances will produce the same name, skip them.
diff --git a/src/libslic3r/Model.hpp b/src/libslic3r/Model.hpp
index 8a19ba003..5d6f2a9db 100644
--- a/src/libslic3r/Model.hpp
+++ b/src/libslic3r/Model.hpp
@@ -387,6 +387,8 @@ public:
 
     const Transform3d& get_matrix(bool dont_translate = false, bool dont_rotate = false, bool dont_scale = false, bool dont_mirror = false) const { return m_transformation.get_matrix(dont_translate, dont_rotate, dont_scale, dont_mirror); }
 
+    using ModelBase::set_new_unique_id;
+
 protected:
 	friend class Print;
     friend class SLAPrint;
@@ -609,8 +611,8 @@ public:
     static std::string get_auto_extruder_id_as_string(unsigned int max_extruders);
     static void reset_auto_extruder_id();
 
-    // Propose an output file name based on the first printable object's name.
-    std::string         propose_export_file_name() const;
+    // Propose an output file name & path based on the first printable object's name and source input file's path.
+    std::string         propose_export_file_name_and_path() const;
 
 private:
     MODELBASE_DERIVED_PRIVATE_COPY_MOVE(Model)
diff --git a/src/libslic3r/PlaceholderParser.hpp b/src/libslic3r/PlaceholderParser.hpp
index b5ed56fa1..22c790e6b 100644
--- a/src/libslic3r/PlaceholderParser.hpp
+++ b/src/libslic3r/PlaceholderParser.hpp
@@ -32,7 +32,8 @@ public:
     void set(const std::string &key, double value)              { this->set(key, new ConfigOptionFloat(value)); }
     void set(const std::string &key, const std::vector<std::string> &values) { this->set(key, new ConfigOptionStrings(values)); }
     void set(const std::string &key, ConfigOption *opt)         { m_config.set_key_value(key, opt); }
-    const DynamicConfig&    config() const                      { return m_config; }
+	DynamicConfig&			config_writable()					{ return m_config; }
+	const DynamicConfig&    config() const                      { return m_config; }
     const ConfigOption*     option(const std::string &key) const { return m_config.option(key); }
 
     // Fill in the template using a macro processing language.
diff --git a/src/libslic3r/Print.cpp b/src/libslic3r/Print.cpp
index 42fda92fe..bc692ca90 100644
--- a/src/libslic3r/Print.cpp
+++ b/src/libslic3r/Print.cpp
@@ -421,8 +421,6 @@ void Print::add_model_object(ModelObject* model_object, int idx)
         src_normalized.normalize();
         object->config_apply(src_normalized, true);
     }
-    
-    this->update_object_placeholders();
 }
 
 bool Print::apply_config(DynamicPrintConfig config)
@@ -1096,9 +1094,6 @@ Print::ApplyStatus Print::apply(const Model &model, const DynamicPrintConfig &co
         }
     }
 
-    //FIXME there may be a race condition with the G-code export running at the background thread.
-    this->update_object_placeholders();
-
 #ifdef _DEBUG
     check_model_ids_equal(m_model, model);
 #endif /* _DEBUG */
@@ -1855,6 +1850,9 @@ int Print::get_extruder(const ExtrusionEntityCollection& fill, const PrintRegion
                                     std::max<int>(region.config().perimeter_extruder.value - 1, 0);
 }
 
+// Generate a recommended G-code output file name based on the format template, default extension, and template parameters
+// (timestamps, object placeholders derived from the model, current placeholder prameters and print statistics.
+// Use the final print statistics if available, or just keep the print statistics placeholders if not available yet (before G-code is finalized).
 std::string Print::output_filename() const 
 { 
     // Set the placeholders for the data know first after the G-code export is finished.
diff --git a/src/libslic3r/PrintBase.cpp b/src/libslic3r/PrintBase.cpp
index 48e991b8d..3fe9a2b4d 100644
--- a/src/libslic3r/PrintBase.cpp
+++ b/src/libslic3r/PrintBase.cpp
@@ -15,7 +15,7 @@ namespace Slic3r
 size_t PrintStateBase::g_last_timestamp = 0;
 
 // Update "scale", "input_filename", "input_filename_base" placeholders from the current m_objects.
-void PrintBase::update_object_placeholders()
+void PrintBase::update_object_placeholders(DynamicConfig &config) const
 {
     // get the first input file name
     std::string input_file;
@@ -33,27 +33,29 @@ void PrintBase::update_object_placeholders()
 				"% y:" + boost::lexical_cast<std::string>(printable->get_scaling_factor(Y) * 100) +
 				"% z:" + boost::lexical_cast<std::string>(printable->get_scaling_factor(Z) * 100) + "%");
 	        if (input_file.empty())
-	            input_file = model_object->input_file;
+	            input_file = model_object->name.empty() ? model_object->input_file : model_object->name;
 	    }
     }
     
-    PlaceholderParser &pp = m_placeholder_parser;
-    pp.set("scale", v_scale);
+    config.set_key_value("year", new ConfigOptionStrings(v_scale));
     if (! input_file.empty()) {
         // get basename with and without suffix
         const std::string input_basename = boost::filesystem::path(input_file).filename().string();
-        pp.set("input_filename", input_basename);
+        config.set_key_value("input_filename", new ConfigOptionString(input_basename));
         const std::string input_basename_base = input_basename.substr(0, input_basename.find_last_of("."));
-        pp.set("input_filename_base", input_basename_base);
+        config.set_key_value("input_filename_base", new ConfigOptionString(input_basename_base));
     }
 }
 
+// Generate an output file name based on the format template, default extension, and template parameters
+// (timestamps, object placeholders derived from the model, current placeholder prameters, print statistics - config_override)
 std::string PrintBase::output_filename(const std::string &format, const std::string &default_ext, const DynamicConfig *config_override) const
 {
     DynamicConfig cfg;
     if (config_override != nullptr)
     	cfg = *config_override;
     PlaceholderParser::update_timestamp(cfg);
+    this->update_object_placeholders(cfg);
     try {
         boost::filesystem::path filename = this->placeholder_parser().process(format, 0, &cfg);
         if (filename.extension().empty())
@@ -69,7 +71,7 @@ std::string PrintBase::output_filepath(const std::string &path) const
     // if we were supplied no path, generate an automatic one based on our first object's input file
     if (path.empty())
         // get the first input file name
-        return (boost::filesystem::path(m_model.propose_export_file_name()).parent_path() / this->output_filename()).make_preferred().string();
+        return (boost::filesystem::path(m_model.propose_export_file_name_and_path()).parent_path() / this->output_filename()).make_preferred().string();
     
     // if we were supplied a directory, use it and append our automatically generated filename
     boost::filesystem::path p(path);
diff --git a/src/libslic3r/PrintBase.hpp b/src/libslic3r/PrintBase.hpp
index 1a61921d6..84d04d26f 100644
--- a/src/libslic3r/PrintBase.hpp
+++ b/src/libslic3r/PrintBase.hpp
@@ -309,7 +309,7 @@ protected:
     // To be called by this->output_filename() with the format string pulled from the configuration layer.
     std::string            output_filename(const std::string &format, const std::string &default_ext, const DynamicConfig *config_override = nullptr) const;
     // Update "scale", "input_filename", "input_filename_base" placeholders from the current printable ModelObjects.
-    void                   update_object_placeholders();
+    void                   update_object_placeholders(DynamicConfig &config) const;
 
 	Model                                   m_model;
 
diff --git a/src/libslic3r/SLAPrint.cpp b/src/libslic3r/SLAPrint.cpp
index 673625e85..a4e554d8e 100644
--- a/src/libslic3r/SLAPrint.cpp
+++ b/src/libslic3r/SLAPrint.cpp
@@ -387,8 +387,6 @@ SLAPrint::ApplyStatus SLAPrint::apply(const Model &model, const DynamicPrintConf
             update_apply_status(false);
     }
 
-    this->update_object_placeholders();
-
 #ifdef _DEBUG
     check_model_ids_equal(m_model, model);
 #endif /* _DEBUG */
diff --git a/src/libslic3r/Utils.hpp b/src/libslic3r/Utils.hpp
index ed12d0559..046745e6f 100644
--- a/src/libslic3r/Utils.hpp
+++ b/src/libslic3r/Utils.hpp
@@ -8,6 +8,8 @@
 
 #include "libslic3r.h"
 
+namespace boost { namespace filesystem { class directory_entry; }}
+
 namespace Slic3r {
 
 extern void set_logging_level(unsigned int level);
@@ -61,6 +63,12 @@ extern int rename_file(const std::string &from, const std::string &to);
 // Copy a file, adjust the access attributes, so that the target is writable.
 extern int copy_file(const std::string &from, const std::string &to);
 
+// Ignore system and hidden files, which may be created by the DropBox synchronisation process.
+// https://github.com/prusa3d/Slic3r/issues/1298
+extern bool is_plain_file(const boost::filesystem::directory_entry &path);
+extern bool is_ini_file(const boost::filesystem::directory_entry &path);
+extern bool is_idx_file(const boost::filesystem::directory_entry &path);
+
 // File path / name / extension splitting utilities, working with UTF-8,
 // to be published to Perl.
 namespace PerlUtils {
diff --git a/src/libslic3r/utils.cpp b/src/libslic3r/utils.cpp
index f48abfd89..6727bb799 100644
--- a/src/libslic3r/utils.cpp
+++ b/src/libslic3r/utils.cpp
@@ -30,7 +30,13 @@
 
 #include <tbb/task_scheduler_init.h>
 
-#include <tbb/task_scheduler_init.h>
+#if defined(__linux) || defined(__GNUC__ )
+#include <strings.h>
+#endif /* __linux */
+
+#ifdef _MSC_VER 
+    #define strcasecmp _stricmp
+#endif
 
 namespace Slic3r {
 
@@ -248,6 +254,30 @@ int copy_file(const std::string &from, const std::string &to)
     return 0;
 }
 
+// Ignore system and hidden files, which may be created by the DropBox synchronisation process.
+// https://github.com/prusa3d/Slic3r/issues/1298
+bool is_plain_file(const boost::filesystem::directory_entry &dir_entry)
+{
+    if (! boost::filesystem::is_regular_file(dir_entry.status()))
+        return false;
+#ifdef _MSC_VER
+    DWORD attributes = GetFileAttributesW(boost::nowide::widen(dir_entry.path().string()).c_str());
+    return (attributes & (FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_SYSTEM)) == 0;
+#else
+    return true;
+#endif
+}
+
+bool is_ini_file(const boost::filesystem::directory_entry &dir_entry)
+{
+    return is_plain_file(dir_entry) && strcasecmp(dir_entry.path().extension().string().c_str(), ".ini") == 0;
+}
+
+bool is_idx_file(const boost::filesystem::directory_entry &dir_entry)
+{
+	return is_plain_file(dir_entry) && strcasecmp(dir_entry.path().extension().string().c_str(), ".idx") == 0;
+}
+
 } // namespace Slic3r
 
 #ifdef WIN32
diff --git a/src/slic3r.cpp b/src/slic3r.cpp
index 0b7dada70..62b56f7ff 100644
--- a/src/slic3r.cpp
+++ b/src/slic3r.cpp
@@ -252,10 +252,6 @@ int main(int argc, char **argv)
                 model.arrange_objects(fff_print.config().min_object_distance());
                 model.center_instances_around_point(cli_config.print_center);
             }
-            if (outfile.empty()) {
-                outfile = model.propose_export_file_name();
-                outfile += (printer_technology == ptFFF) ? ".gcode" : ".zip";
-            }
             if (printer_technology == ptFFF) {
                 for (auto* mo : model.objects)
                     fff_print.auto_assign_extruders(mo);
@@ -265,6 +261,7 @@ int main(int argc, char **argv)
             std::string err = print->validate();
             if (err.empty()) {
                 if (printer_technology == ptFFF) {
+                    // The outfile is processed by a PlaceholderParser.
                     fff_print.export_gcode(outfile, nullptr);
                 } else {
                     assert(printer_technology == ptSLA);
diff --git a/src/slic3r/Config/Snapshot.cpp b/src/slic3r/Config/Snapshot.cpp
index 35bfde0b6..b208554b5 100644
--- a/src/slic3r/Config/Snapshot.cpp
+++ b/src/slic3r/Config/Snapshot.cpp
@@ -249,10 +249,10 @@ bool Snapshot::equal_to_active(const AppConfig &app_config) const
         boost::filesystem::path path2 = snapshot_dir / subdir;
         std::vector<std::string> files1, files2;
         for (auto &dir_entry : boost::filesystem::directory_iterator(path1))
-            if (boost::filesystem::is_regular_file(dir_entry.status()) && boost::algorithm::iends_with(dir_entry.path().filename().string(), ".ini"))
+            if (Slic3r::is_ini_file(dir_entry))
                 files1.emplace_back(dir_entry.path().filename().string());
         for (auto &dir_entry : boost::filesystem::directory_iterator(path2))
-            if (boost::filesystem::is_regular_file(dir_entry.status()) && boost::algorithm::iends_with(dir_entry.path().filename().string(), ".ini"))
+            if (Slic3r::is_ini_file(dir_entry))
                 files2.emplace_back(dir_entry.path().filename().string());
         std::sort(files1.begin(), files1.end());
         std::sort(files2.begin(), files2.end());
@@ -343,7 +343,7 @@ static void copy_config_dir_single_level(const boost::filesystem::path &path_src
         throw std::runtime_error(std::string("Slic3r was unable to create a directory at ") + path_dst.string());
 
 	for (auto &dir_entry : boost::filesystem::directory_iterator(path_src))
-        if (boost::filesystem::is_regular_file(dir_entry.status()) && boost::algorithm::iends_with(dir_entry.path().filename().string(), ".ini"))
+        if (Slic3r::is_ini_file(dir_entry))
 		    boost::filesystem::copy_file(dir_entry.path(), path_dst / dir_entry.path().filename(), boost::filesystem::copy_option::overwrite_if_exists);
 }
 
diff --git a/src/slic3r/Config/Version.cpp b/src/slic3r/Config/Version.cpp
index 48ace7b60..70b12f23b 100644
--- a/src/slic3r/Config/Version.cpp
+++ b/src/slic3r/Config/Version.cpp
@@ -297,7 +297,7 @@ std::vector<Index> Index::load_db()
     std::vector<Index> index_db;
     std::string errors_cummulative;
 	for (auto &dir_entry : boost::filesystem::directory_iterator(cache_dir))
-        if (boost::filesystem::is_regular_file(dir_entry.status()) && boost::algorithm::iends_with(dir_entry.path().filename().string(), ".idx")) {
+        if (Slic3r::is_idx_file(dir_entry)) {
         	Index idx;
             try {
             	idx.load(dir_entry.path());
diff --git a/src/slic3r/GUI/ConfigWizard.cpp b/src/slic3r/GUI/ConfigWizard.cpp
index 6cf45166d..3471395c2 100644
--- a/src/slic3r/GUI/ConfigWizard.cpp
+++ b/src/slic3r/GUI/ConfigWizard.cpp
@@ -635,35 +635,32 @@ void ConfigWizard::priv::load_vendors()
 	const auto rsrc_vendor_dir = fs::path(resources_dir()) / "profiles";
 
 	// Load vendors from the "vendors" directory in datadir
-	for (fs::directory_iterator it(vendor_dir); it != fs::directory_iterator(); ++it) {
-		if (it->path().extension() == ".ini") {
+    for (auto &dir_entry : boost::filesystem::directory_iterator(vendor_dir))
+		if (Slic3r::is_ini_file(dir_entry)) {
 			try {
-				auto vp = VendorProfile::from_ini(it->path());
+				auto vp = VendorProfile::from_ini(dir_entry.path());
 				vendors[vp.id] = std::move(vp);
 			}
 			catch (const std::exception& e) {
-				BOOST_LOG_TRIVIAL(error) << boost::format("Error loading vendor bundle %1%: %2%") % it->path() % e.what();
+				BOOST_LOG_TRIVIAL(error) << boost::format("Error loading vendor bundle %1%: %2%") % dir_entry.path() % e.what();
 			}
-
 		}
-	}
 
 	// Additionally load up vendors from the application resources directory, but only those not seen in the datadir
-	for (fs::directory_iterator it(rsrc_vendor_dir); it != fs::directory_iterator(); ++it) {
-		if (it->path().extension() == ".ini") {
-			const auto id = it->path().stem().string();
+    for (auto &dir_entry : boost::filesystem::directory_iterator(rsrc_vendor_dir))
+		if (Slic3r::is_ini_file(dir_entry)) {
+			const auto id = dir_entry.path().stem().string();
 			if (vendors.find(id) == vendors.end()) {
 				try {
-					auto vp = VendorProfile::from_ini(it->path());
-					vendors_rsrc[vp.id] = it->path().filename().string();
+					auto vp = VendorProfile::from_ini(dir_entry.path());
+					vendors_rsrc[vp.id] = dir_entry.path().filename().string();
 					vendors[vp.id] = std::move(vp);
 				}
 				catch (const std::exception& e) {
-					BOOST_LOG_TRIVIAL(error) << boost::format("Error loading vendor bundle %1%: %2%") % it->path() % e.what();
+					BOOST_LOG_TRIVIAL(error) << boost::format("Error loading vendor bundle %1%: %2%") % dir_entry.path() % e.what();
 				}
 			}
 		}
-	}
 
 	// Load up the set of vendors / models / variants the user has had enabled up till now
 	const AppConfig *app_config = GUI::get_app_config();
@@ -672,14 +669,15 @@ void ConfigWizard::priv::load_vendors()
 	} else {
 		// In case of legacy datadir, try to guess the preference based on the printer preset files that are present
 		const auto printer_dir = fs::path(Slic3r::data_dir()) / "printer";
-		for (fs::directory_iterator it(printer_dir); it != fs::directory_iterator(); ++it) {
-			auto needle = legacy_preset_map.find(it->path().filename().string());
-			if (needle == legacy_preset_map.end()) { continue; }
+	    for (auto &dir_entry : boost::filesystem::directory_iterator(printer_dir))
+	    	if (Slic3r::is_ini_file(dir_entry)) {
+				auto needle = legacy_preset_map.find(dir_entry.path().filename().string());
+				if (needle == legacy_preset_map.end()) { continue; }
 
-			const auto &model = needle->second.first;
-			const auto &variant = needle->second.second;
-			appconfig_vendors.set_variant("PrusaResearch", model, variant, true);
-		}
+				const auto &model = needle->second.first;
+				const auto &variant = needle->second.second;
+				appconfig_vendors.set_variant("PrusaResearch", model, variant, true);
+			}
 	}
 }
 
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 919c68662..2ee322ebe 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -3987,6 +3987,7 @@ wxDEFINE_EVENT(EVT_GLCANVAS_VIEWPORT_CHANGED, SimpleEvent);
 wxDEFINE_EVENT(EVT_GLCANVAS_RIGHT_CLICK, Vec2dEvent);
 wxDEFINE_EVENT(EVT_GLCANVAS_REMOVE_OBJECT, SimpleEvent);
 wxDEFINE_EVENT(EVT_GLCANVAS_ARRANGE, SimpleEvent);
+wxDEFINE_EVENT(EVT_GLCANVAS_SELECT_ALL, SimpleEvent);
 wxDEFINE_EVENT(EVT_GLCANVAS_QUESTION_MARK, SimpleEvent);
 wxDEFINE_EVENT(EVT_GLCANVAS_INCREASE_INSTANCES, Event<int>);
 wxDEFINE_EVENT(EVT_GLCANVAS_INSTANCE_MOVED, SimpleEvent);
@@ -4442,6 +4443,7 @@ void GLCanvas3D::update_toolbar_items_visibility()
     ConfigOptionMode mode = wxGetApp().get_mode();
     m_toolbar.set_item_visible("more", mode != comSimple);
     m_toolbar.set_item_visible("fewer", mode != comSimple);
+    m_toolbar.set_item_visible("splitvolumes", mode != comSimple);
     m_dirty = true;
 }
 #endif // ENABLE_MODE_AWARE_TOOLBAR_ITEMS
@@ -5068,7 +5070,6 @@ void GLCanvas3D::bind_event_handlers()
         m_canvas->Bind(wxEVT_MIDDLE_DCLICK, &GLCanvas3D::on_mouse, this);
         m_canvas->Bind(wxEVT_RIGHT_DCLICK, &GLCanvas3D::on_mouse, this);
         m_canvas->Bind(wxEVT_PAINT, &GLCanvas3D::on_paint, this);
-        m_canvas->Bind(wxEVT_KEY_DOWN, &GLCanvas3D::on_key_down, this);
     }
 }
 
@@ -5082,7 +5083,7 @@ void GLCanvas3D::unbind_event_handlers()
         m_canvas->Unbind(wxEVT_MOUSEWHEEL, &GLCanvas3D::on_mouse_wheel, this);
         m_canvas->Unbind(wxEVT_TIMER, &GLCanvas3D::on_timer, this);
         m_canvas->Unbind(wxEVT_LEFT_DOWN, &GLCanvas3D::on_mouse, this);
-        m_canvas->Unbind(wxEVT_LEFT_UP, &GLCanvas3D::on_mouse, this);
+		m_canvas->Unbind(wxEVT_LEFT_UP, &GLCanvas3D::on_mouse, this);
         m_canvas->Unbind(wxEVT_MIDDLE_DOWN, &GLCanvas3D::on_mouse, this);
         m_canvas->Unbind(wxEVT_MIDDLE_UP, &GLCanvas3D::on_mouse, this);
         m_canvas->Unbind(wxEVT_RIGHT_DOWN, &GLCanvas3D::on_mouse, this);
@@ -5094,7 +5095,6 @@ void GLCanvas3D::unbind_event_handlers()
         m_canvas->Unbind(wxEVT_MIDDLE_DCLICK, &GLCanvas3D::on_mouse, this);
         m_canvas->Unbind(wxEVT_RIGHT_DCLICK, &GLCanvas3D::on_mouse, this);
         m_canvas->Unbind(wxEVT_PAINT, &GLCanvas3D::on_paint, this);
-        m_canvas->Unbind(wxEVT_KEY_DOWN, &GLCanvas3D::on_key_down, this);
     }
 }
 
@@ -5113,71 +5113,64 @@ void GLCanvas3D::on_idle(wxIdleEvent& evt)
 
 void GLCanvas3D::on_char(wxKeyEvent& evt)
 {
-    if (evt.HasModifiers())
+    // see include/wx/defs.h enum wxKeyCode
+    int keyCode = evt.GetKeyCode();
+    int ctrlMask = wxMOD_CONTROL;
+#ifdef __APPLE__
+    ctrlMask |= wxMOD_RAW_CONTROL;
+#endif /* __APPLE__ */
+    if ((evt.GetModifiers() & ctrlMask) != 0) {
+        switch (keyCode) {
+        case WXK_CONTROL_A: post_event(SimpleEvent(EVT_GLCANVAS_SELECT_ALL)); break;
+#ifdef __APPLE__
+        case WXK_BACK: // the low cost Apple solutions are not equipped with a Delete key, use Backspace instead.
+#endif /* __APPLE__ */
+        case WXK_DELETE:    post_event(SimpleEvent(EVT_GLTOOLBAR_DELETE_ALL)); break;
+        default:            evt.Skip();
+        }
+    } else if (evt.HasModifiers()) {
         evt.Skip();
-    else
-    {
-        int keyCode = evt.GetKeyCode();
-        switch (keyCode - 48)
+    } else {
+        switch (keyCode)
         {
-        // numerical input
-        case 0: { select_view("iso"); break; }
-        case 1: { select_view("top"); break; }
-        case 2: { select_view("bottom"); break; }
-        case 3: { select_view("front"); break; }
-        case 4: { select_view("rear"); break; }
-        case 5: { select_view("left"); break; }
-        case 6: { select_view("right"); break; }
+        // key ESC
+        case WXK_ESCAPE: { m_gizmos.reset_all_states(); m_dirty = true;  break; }
+#ifdef __APPLE__
+        case WXK_BACK: // the low cost Apple solutions are not equipped with a Delete key, use Backspace instead.
+#endif /* __APPLE__ */
+        case WXK_DELETE: post_event(SimpleEvent(EVT_GLTOOLBAR_DELETE)); break;
+        case '0': { select_view("iso"); break; }
+        case '1': { select_view("top"); break; }
+        case '2': { select_view("bottom"); break; }
+        case '3': { select_view("front"); break; }
+        case '4': { select_view("rear"); break; }
+        case '5': { select_view("left"); break; }
+        case '6': { select_view("right"); break; }
+        case '+': { post_event(Event<int>(EVT_GLCANVAS_INCREASE_INSTANCES, +1)); break; }
+        case '-': { post_event(Event<int>(EVT_GLCANVAS_INCREASE_INSTANCES, -1)); break; }
+        case '?': { post_event(SimpleEvent(EVT_GLCANVAS_QUESTION_MARK)); break; }
+        case 'A':
+        case 'a': { post_event(SimpleEvent(EVT_GLCANVAS_ARRANGE)); break; }
+        case 'B':
+        case 'b': { zoom_to_bed(); break; }
+        case 'I':
+        case 'i': { set_camera_zoom(1.0f); break; }
+        case 'O':
+        case 'o': { set_camera_zoom(-1.0f); break; }
+        case 'Z':
+        case 'z': { m_selection.is_empty() ? zoom_to_volumes() : zoom_to_selection(); break; }
         default:
+        {
+            if (m_gizmos.handle_shortcut(keyCode, m_selection))
             {
-                // text input
-                switch (keyCode)
-                {
-                // key ESC
-                case 27: { m_gizmos.reset_all_states(); m_dirty = true;  break; }
-                // key +
-                case 43: { post_event(Event<int>(EVT_GLCANVAS_INCREASE_INSTANCES, +1)); break; }
-                // key -
-                case 45: { post_event(Event<int>(EVT_GLCANVAS_INCREASE_INSTANCES, -1)); break; }
-                // key ?
-                case 63: { post_event(SimpleEvent(EVT_GLCANVAS_QUESTION_MARK)); break; }
-                // key A/a
-                case 65:
-                case 97: { post_event(SimpleEvent(EVT_GLCANVAS_ARRANGE)); break; }
-                // key B/b
-                case 66:
-                case 98: { zoom_to_bed(); break; }
-                // key I/i
-                case 73:
-                case 105: { set_camera_zoom(1.0f); break; }
-                // key O/o
-                case 79:
-                case 111: { set_camera_zoom(-1.0f); break; }
-                // key Z/z
-                case 90:
-                case 122:
-                {
-                    if (m_selection.is_empty())
-                        zoom_to_volumes();
-                    else
-                        zoom_to_selection();
-
-                    break;
-                }
-                default:
-                {
-                    if (m_gizmos.handle_shortcut(keyCode, m_selection))
-                    {
-                        _update_gizmos_data();
-                        m_dirty = true;
-                    }
-                    else
-                        evt.Skip();
-
-                    break;
-                }
-                }
+                _update_gizmos_data();
+                m_dirty = true;
             }
+            else
+                evt.Skip();
+
+            break;
+        }
         }
     }
 }
@@ -5692,24 +5685,6 @@ void GLCanvas3D::on_paint(wxPaintEvent& evt)
         this->render();
 }
 
-void GLCanvas3D::on_key_down(wxKeyEvent& evt)
-{
-    if (evt.HasModifiers())
-        evt.Skip();
-    else
-    {
-        int key = evt.GetKeyCode();
-#ifdef __WXOSX__
-        if (key == WXK_BACK)
-#else
-        if (key == WXK_DELETE)
-#endif // __WXOSX__
-            post_event(SimpleEvent(EVT_GLCANVAS_REMOVE_OBJECT));
-        else
-            evt.Skip();
-    }
-}
-
 Size GLCanvas3D::get_canvas_size() const
 {
     int w = 0;
@@ -6087,7 +6062,7 @@ bool GLCanvas3D::_init_toolbar()
     GLToolbarItem::Data item;
 
     item.name = "add";
-    item.tooltip = GUI::L_str("Add... [Ctrl+I]");
+    item.tooltip = GUI::L_str("Add...") + " [" + GUI::shortkey_ctrl_prefix() + "I]";
     item.sprite_id = 0;
     item.is_toggable = false;
     item.action_event = EVT_GLTOOLBAR_ADD;
@@ -6095,7 +6070,7 @@ bool GLCanvas3D::_init_toolbar()
         return false;
 
     item.name = "delete";
-    item.tooltip = GUI::L_str("Delete [Del]");
+    item.tooltip = GUI::L_str("Delete") + " [Del]";
     item.sprite_id = 1;
     item.is_toggable = false;
     item.action_event = EVT_GLTOOLBAR_DELETE;
@@ -6103,7 +6078,7 @@ bool GLCanvas3D::_init_toolbar()
         return false;
 
     item.name = "deleteall";
-    item.tooltip = GUI::L_str("Delete all [Ctrl+Del]");
+    item.tooltip = GUI::L_str("Delete all") + " [" + GUI::shortkey_ctrl_prefix() + "Del]";
     item.sprite_id = 2;
     item.is_toggable = false;
     item.action_event = EVT_GLTOOLBAR_DELETE_ALL;
diff --git a/src/slic3r/GUI/GLCanvas3D.hpp b/src/slic3r/GUI/GLCanvas3D.hpp
index 34e3df2a7..84a162082 100644
--- a/src/slic3r/GUI/GLCanvas3D.hpp
+++ b/src/slic3r/GUI/GLCanvas3D.hpp
@@ -121,6 +121,7 @@ wxDECLARE_EVENT(EVT_GLCANVAS_VIEWPORT_CHANGED, SimpleEvent);
 wxDECLARE_EVENT(EVT_GLCANVAS_RIGHT_CLICK, Vec2dEvent);
 wxDECLARE_EVENT(EVT_GLCANVAS_REMOVE_OBJECT, SimpleEvent);
 wxDECLARE_EVENT(EVT_GLCANVAS_ARRANGE, SimpleEvent);
+wxDECLARE_EVENT(EVT_GLCANVAS_SELECT_ALL, SimpleEvent);
 wxDECLARE_EVENT(EVT_GLCANVAS_QUESTION_MARK, SimpleEvent);
 wxDECLARE_EVENT(EVT_GLCANVAS_INCREASE_INSTANCES, Event<int>); // data: +1 => increase, -1 => decrease
 wxDECLARE_EVENT(EVT_GLCANVAS_INSTANCE_MOVED, SimpleEvent);
@@ -1042,7 +1043,6 @@ public:
     void on_timer(wxTimerEvent& evt);
     void on_mouse(wxMouseEvent& evt);
     void on_paint(wxPaintEvent& evt);
-    void on_key_down(wxKeyEvent& evt);
 
     Size get_canvas_size() const;
     Point get_local_mouse_position() const;
diff --git a/src/slic3r/GUI/GUI.cpp b/src/slic3r/GUI/GUI.cpp
index 148285e86..8e80d64c3 100644
--- a/src/slic3r/GUI/GUI.cpp
+++ b/src/slic3r/GUI/GUI.cpp
@@ -75,6 +75,30 @@ void break_to_debugger()
     #endif /* _WIN32 */
 }
 
+const std::string& shortkey_ctrl_prefix()
+{
+	static const std::string str = 
+#ifdef __APPLE__
+		"⌘"
+#else
+		"Ctrl+"
+#endif
+		;
+	return str;
+}
+
+const std::string& shortkey_alt_prefix()
+{
+	static const std::string str = 
+#ifdef __APPLE__
+		"⌥"
+#else
+		"Alt+"
+#endif
+		;
+	return str;
+}
+
 bool config_wizard_startup(bool app_config_exists)
 {
     if (!app_config_exists || wxGetApp().preset_bundle->printers.size() <= 1) {
diff --git a/src/slic3r/GUI/GUI.hpp b/src/slic3r/GUI/GUI.hpp
index e33be8f58..f066c82a8 100644
--- a/src/slic3r/GUI/GUI.hpp
+++ b/src/slic3r/GUI/GUI.hpp
@@ -27,7 +27,11 @@ void enable_screensaver();
 bool debugged();
 void break_to_debugger();
 
-AppConfig*		get_app_config();
+// Platform specific Ctrl+/Alt+ (Windows, Linux) vs. ⌘/⌥ (OSX) prefixes 
+extern const std::string& shortkey_ctrl_prefix();
+extern const std::string& shortkey_alt_prefix();
+
+extern AppConfig* get_app_config();
 
 extern void add_menus(wxMenuBar *menu, int event_preferences_changed, int event_language_change);
 
diff --git a/src/slic3r/GUI/GUI_App.cpp b/src/slic3r/GUI/GUI_App.cpp
index 9991d98ea..056062cf4 100644
--- a/src/slic3r/GUI/GUI_App.cpp
+++ b/src/slic3r/GUI/GUI_App.cpp
@@ -561,7 +561,13 @@ void GUI_App::add_config_menu(wxMenuBar *menu)
     local_menu->Append(config_id_base + ConfigMenuTakeSnapshot, _(L("Take Configuration &Snapshot")), _(L("Capture a configuration snapshot")));
     // 	local_menu->Append(config_id_base + ConfigMenuUpdate, 		_(L("Check for updates")), 					_(L("Check for configuration updates")));
     local_menu->AppendSeparator();
-    local_menu->Append(config_id_base + ConfigMenuPreferences, _(L("&Preferences")) + dots + "\tCtrl+P", _(L("Application preferences")));
+    local_menu->Append(config_id_base + ConfigMenuPreferences, _(L("&Preferences")) + dots + 
+#ifdef __APPLE__
+        "\tCtrl+,",
+#else
+        "\tCtrl+P",
+#endif
+        _(L("Application preferences")));
     local_menu->AppendSeparator();
     auto mode_menu = new wxMenu();
     mode_menu->AppendRadioItem(config_id_base + ConfigMenuModeSimple, _(L("Simple")), _(L("Simple View Mode")));
diff --git a/src/slic3r/GUI/KBShortcutsDialog.cpp b/src/slic3r/GUI/KBShortcutsDialog.cpp
index 3aeda0348..d893d6f76 100644
--- a/src/slic3r/GUI/KBShortcutsDialog.cpp
+++ b/src/slic3r/GUI/KBShortcutsDialog.cpp
@@ -88,13 +88,8 @@ KBShortcutsDialog::KBShortcutsDialog()
 
 void KBShortcutsDialog::fill_shortcuts()
 {
-#ifdef __WXOSX__
-    const std::string ctrl = "⌘";
-    const std::string alt = "⌥";
-#else
-    const std::string ctrl = "Ctrl+";
-    const std::string alt = "Alt+";
-#endif // __WXOSX__
+    const std::string &ctrl = GUI::shortkey_ctrl_prefix();
+    const std::string &alt  = GUI::shortkey_alt_prefix();
 
     m_full_shortcuts.reserve(4);
 
diff --git a/src/slic3r/GUI/MainFrame.cpp b/src/slic3r/GUI/MainFrame.cpp
index 947dd59bd..78dffa1cb 100644
--- a/src/slic3r/GUI/MainFrame.cpp
+++ b/src/slic3r/GUI/MainFrame.cpp
@@ -324,7 +324,19 @@ void MainFrame::init_menubar()
     if (m_plater != nullptr)
     {
         editMenu = new wxMenu();
-        wxMenuItem* item_select_all = append_menu_item(editMenu, wxID_ANY, _(L("&Select all")) + "\tCtrl+A", _(L("Selects all objects")),
+        // \xA0 is a non-breaking space. It is entered here to spoil the automatic accelerators,
+        // as the simple numeric accelerators spoil all numeric data entry.
+        wxMenuItem* item_select_all = append_menu_item(editMenu, wxID_ANY, _(L("&Select all")) +
+#ifdef _MSC_VER
+            "\t\xA0" + "Ctrl+\xA0" + "A"
+#else
+#ifdef __APPLE__
+            "\tCtrl+A"
+#else
+            " - Ctrl+A"
+#endif
+#endif
+            , _(L("Selects all objects")),
             [this](wxCommandEvent&) { m_plater->select_all(); }, "");
         editMenu->AppendSeparator();
         wxMenuItem* item_delete_sel = append_menu_item(editMenu, wxID_ANY, _(L("&Delete selected")) + "\tDel", _(L("Deletes the current selection")),
@@ -386,19 +398,23 @@ void MainFrame::init_menubar()
 
     // View menu
     wxMenu* viewMenu = nullptr;
+    wxString sep =
+#ifdef _MSC_VER
+        "\t";
+#else
+        " - ";
+#endif
     if (m_plater) {
         viewMenu = new wxMenu();
-        // \xA0 is a non-breaing space. It is entered here to spoil the automatic accelerators,
-        // as the simple numeric accelerators spoil all numeric data entry.
         // The camera control accelerators are captured by GLCanvas3D::on_char().
-        wxMenuItem* item_iso = append_menu_item(viewMenu, wxID_ANY, _(L("&Iso")) + "\t\xA0" + "0", _(L("Iso View")), [this](wxCommandEvent&) { select_view("iso"); });
+		wxMenuItem* item_iso = append_menu_item(viewMenu, wxID_ANY, _(L("Iso")) + sep + "&0", _(L("Iso View")), [this](wxCommandEvent&) { select_view("iso"); });
         viewMenu->AppendSeparator();
-        wxMenuItem* item_top = append_menu_item(viewMenu, wxID_ANY, _(L("&Top")) + "\t\xA0" + "1", _(L("Top View")), [this](wxCommandEvent&) { select_view("top"); });
-        wxMenuItem* item_bottom = append_menu_item(viewMenu, wxID_ANY, _(L("&Bottom")) + "\t\xA0" + "2", _(L("Bottom View")), [this](wxCommandEvent&) { select_view("bottom"); });
-        wxMenuItem* item_front = append_menu_item(viewMenu, wxID_ANY, _(L("&Front")) + "\t\xA0" + "3", _(L("Front View")), [this](wxCommandEvent&) { select_view("front"); });
-        wxMenuItem* item_rear = append_menu_item(viewMenu, wxID_ANY, _(L("R&ear")) + "\t\xA0" + "4", _(L("Rear View")), [this](wxCommandEvent&) { select_view("rear"); });
-        wxMenuItem* item_left = append_menu_item(viewMenu, wxID_ANY, _(L("&Left")) + "\t\xA0" + "5", _(L("Left View")), [this](wxCommandEvent&) { select_view("left"); });
-        wxMenuItem* item_right = append_menu_item(viewMenu, wxID_ANY, _(L("&Right")) + "\t\xA0" + "6", _(L("Right View")), [this](wxCommandEvent&) { select_view("right"); });
+		wxMenuItem* item_top = append_menu_item(viewMenu, wxID_ANY, _(L("Top")) + sep + "&1", _(L("Top View")), [this](wxCommandEvent&) { select_view("top"); });
+		wxMenuItem* item_bottom = append_menu_item(viewMenu, wxID_ANY, _(L("Bottom")) + sep + "&2", _(L("Bottom View")), [this](wxCommandEvent&) { select_view("bottom"); });
+		wxMenuItem* item_front = append_menu_item(viewMenu, wxID_ANY, _(L("Front")) + sep + "&3", _(L("Front View")), [this](wxCommandEvent&) { select_view("front"); });
+		wxMenuItem* item_rear = append_menu_item(viewMenu, wxID_ANY, _(L("Rear")) + sep + "&4", _(L("Rear View")), [this](wxCommandEvent&) { select_view("rear"); });
+		wxMenuItem* item_left = append_menu_item(viewMenu, wxID_ANY, _(L("Left")) + sep + "&5", _(L("Left View")), [this](wxCommandEvent&) { select_view("left"); });
+		wxMenuItem* item_right = append_menu_item(viewMenu, wxID_ANY, _(L("Right")) + sep + "&6", _(L("Right View")), [this](wxCommandEvent&) { select_view("right"); });
 
         Bind(wxEVT_UPDATE_UI, [this](wxUpdateUIEvent& evt) { evt.Enable(can_change_view()); }, item_iso->GetId());
         Bind(wxEVT_UPDATE_UI, [this](wxUpdateUIEvent& evt) { evt.Enable(can_change_view()); }, item_top->GetId());
@@ -434,7 +450,7 @@ void MainFrame::init_menubar()
         append_menu_item(helpMenu, wxID_ANY, _(L("&About Slic3r")), _(L("Show about dialog")),
             [this](wxCommandEvent&) { Slic3r::GUI::about(); });
         helpMenu->AppendSeparator();
-        append_menu_item(helpMenu, wxID_ANY, _(L("&Keyboard Shortcuts")) + "\t\xA0?", _(L("Show the list of the keyboard shortcuts")),
+        append_menu_item(helpMenu, wxID_ANY, _(L("Keyboard Shortcuts")) + sep + "&?", _(L("Show the list of the keyboard shortcuts")),
             [this](wxCommandEvent&) { wxGetApp().keyboard_shortcuts(); });
     }
 
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index edc0fecd6..f9ad7a39a 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -1028,7 +1028,8 @@ struct Plater::priv
     unsigned int update_background_process(bool force_validation = false);
     // Restart background processing thread based on a bitmask of UpdateBackgroundProcessReturnState.
     bool restart_background_process(unsigned int state);
-    void update_restart_background_process(bool force_scene_update, bool force_preview_update);
+	// returns bit mask of UpdateBackgroundProcessReturnState
+	unsigned int update_restart_background_process(bool force_scene_update, bool force_preview_update);
     void export_gcode(fs::path output_path, PrintHostJob upload_job);
     void reload_from_disk();
     void fix_through_netfabb(const int obj_idx, const int vol_idx = -1);
@@ -1170,6 +1171,7 @@ Plater::priv::priv(Plater *q, MainFrame *main_frame)
     view3D_canvas->Bind(EVT_GLCANVAS_RIGHT_CLICK, &priv::on_right_click, this);
     view3D_canvas->Bind(EVT_GLCANVAS_REMOVE_OBJECT, [q](SimpleEvent&) { q->remove_selected(); });
     view3D_canvas->Bind(EVT_GLCANVAS_ARRANGE, [this](SimpleEvent&) { arrange(); });
+    view3D_canvas->Bind(EVT_GLCANVAS_SELECT_ALL, [this](SimpleEvent&) { this->q->select_all(); });
     view3D_canvas->Bind(EVT_GLCANVAS_QUESTION_MARK, [this](SimpleEvent&) { wxGetApp().keyboard_shortcuts(); });
     view3D_canvas->Bind(EVT_GLCANVAS_INCREASE_INSTANCES, [this](Event<int> &evt) 
         { if (evt.data == 1) this->q->increase_instances(); else if (this->can_decrease_instances()) this->q->decrease_instances(); });
@@ -1575,7 +1577,7 @@ std::unique_ptr<CheckboxFileDialog> Plater::priv::get_export_file(GUI::FileType
     // Update printbility state of each of the ModelInstances.
     this->update_print_volume_state();
     // Find the file name of the first printable object.
-	fs::path output_file = this->model.propose_export_file_name();
+	fs::path output_file = this->model.propose_export_file_name_and_path();
 
     switch (file_type) {
         case FT_STL: output_file.replace_extension("stl"); break;
@@ -1735,6 +1737,8 @@ void Plater::priv::arrange()
     // Guard the arrange process
     arranging.store(true);
 
+    wxBusyCursor wait;
+
     // Disable the arrange button (to prevent reentrancies, we will call wxYied)
     view3D->enable_toolbar_item("arrange", can_arrange());
 
@@ -2045,7 +2049,7 @@ void Plater::priv::export_gcode(fs::path output_path, PrintHostJob upload_job)
     this->restart_background_process(priv::UPDATE_BACKGROUND_PROCESS_FORCE_EXPORT);
 }
 
-void Plater::priv::update_restart_background_process(bool force_update_scene, bool force_update_preview)
+unsigned int Plater::priv::update_restart_background_process(bool force_update_scene, bool force_update_preview)
 {
     // bitmask of UpdateBackgroundProcessReturnState
     unsigned int state = this->update_background_process(false);
@@ -2055,6 +2059,7 @@ void Plater::priv::update_restart_background_process(bool force_update_scene, bo
     if (force_update_preview)
         this->preview->reload_print();
     this->restart_background_process(state);
+	return state;
 }
 
 void Plater::priv::update_fff_scene()
@@ -2108,31 +2113,10 @@ void Plater::priv::fix_through_netfabb(const int obj_idx, const int vol_idx/* =
 {
     if (obj_idx < 0)
         return;
-
-    const auto model_object = model.objects[obj_idx];
-    Model model_fixed;// = new Model();
-    fix_model_by_win10_sdk_gui(*model_object, this->fff_print, model_fixed);
-
-    auto new_obj_idxs = load_model_objects(model_fixed.objects);
-    if (new_obj_idxs.empty())
-        return;
-    
-    for(auto new_obj_idx : new_obj_idxs) {
-        auto o = model.objects[new_obj_idx];
-        o->clear_instances();
-        for (auto instance: model_object->instances)
-            o->add_instance(*instance);
-        o->invalidate_bounding_box();
-        
-        if (o->volumes.size() == model_object->volumes.size()) {
-            for (int i = 0; i < o->volumes.size(); i++) {
-                o->volumes[i]->config.apply(model_object->volumes[i]->config);
-            }
-        }
-        // FIXME restore volumes and their configs, layer_height_ranges, layer_height_profile
-    }
-    
-    remove(obj_idx);
+    fix_model_by_win10_sdk_gui(*model.objects[obj_idx], vol_idx);
+    this->object_list_changed();
+    this->update();
+    this->schedule_background_process();
 }
 
 void Plater::priv::set_current_panel(wxPanel* panel)
@@ -2553,7 +2537,7 @@ void Plater::priv::init_view_toolbar()
     GLToolbarItem::Data item;
 
     item.name = "3D";
-    item.tooltip = GUI::L_str("3D editor view [Ctrl+5]");
+    item.tooltip = GUI::L_str("3D editor view") + " [" + GUI::shortkey_ctrl_prefix() + "5]";
     item.sprite_id = 0;
     item.action_event = EVT_GLVIEWTOOLBAR_3D;
     item.is_toggable = false;
@@ -2561,7 +2545,7 @@ void Plater::priv::init_view_toolbar()
         return;
 
     item.name = "Preview";
-    item.tooltip = GUI::L_str("Preview [Ctrl+6]");
+    item.tooltip = GUI::L_str("Preview") + " [" + GUI::shortkey_ctrl_prefix() + "6]";
     item.sprite_id = 1;
     item.action_event = EVT_GLVIEWTOOLBAR_PREVIEW;
     item.is_toggable = false;
@@ -2846,51 +2830,43 @@ void Plater::cut(size_t obj_idx, size_t instance_idx, coordf_t z, bool keep_uppe
     p->load_model_objects(new_objects);
 }
 
-void Plater::export_gcode(fs::path output_path)
+void Plater::export_gcode()
 {
     if (p->model.objects.empty())
         return;
 
-    // select output file
-    if (output_path.empty()) {
-        // XXX: take output path from CLI opts? Ancient Slic3r versions used to do that...
-
-        // If possible, remove accents from accented latin characters.
-        // This function is useful for generating file names to be processed by legacy firmwares.
-        fs::path default_output_file;
-        try {
-            default_output_file = this->p->background_process.current_print()->output_filepath(output_path.string());
-        } catch (const std::exception &ex) {
-            show_error(this, ex.what());
-            return;
-        }
-        default_output_file = fs::path(Slic3r::fold_utf8_to_ascii(default_output_file.string()));
-        auto start_dir = wxGetApp().app_config->get_last_output_dir(default_output_file.parent_path().string());
-
-        wxFileDialog dlg(this, (printer_technology() == ptFFF) ? _(L("Save G-code file as:")) : _(L("Save Zip file as:")),
-            start_dir,
-            from_path(default_output_file.filename()),
-            GUI::file_wildcards((printer_technology() == ptFFF) ? FT_GCODE : FT_PNGZIP, default_output_file.extension().string()),
-            wxFD_SAVE | wxFD_OVERWRITE_PROMPT
-        );
-
-        if (dlg.ShowModal() == wxID_OK) {
-            fs::path path = into_path(dlg.GetPath());
-            wxGetApp().app_config->update_last_output_dir(path.parent_path().string());
-            output_path = std::move(path);
-        }
-    } else {
-        try {
-            output_path = this->p->background_process.current_print()->output_filepath(output_path.string());
-        } catch (const std::exception &ex) {
-            show_error(this, ex.what());
-            return;
-        }
+    // If possible, remove accents from accented latin characters.
+    // This function is useful for generating file names to be processed by legacy firmwares.
+    fs::path default_output_file;
+    try {
+		// Update the background processing, so that the placeholder parser will get the correct values for the ouput file template.
+		// Also if there is something wrong with the current configuration, a pop-up dialog will be shown and the export will not be performed.
+		unsigned int state = this->p->update_restart_background_process(false, false);
+		if (state & priv::UPDATE_BACKGROUND_PROCESS_INVALID)
+			return;
+		default_output_file = this->p->background_process.current_print()->output_filepath("");
+    } catch (const std::exception &ex) {
+        show_error(this, ex.what());
+        return;
     }
+    default_output_file = fs::path(Slic3r::fold_utf8_to_ascii(default_output_file.string()));
+    auto start_dir = wxGetApp().app_config->get_last_output_dir(default_output_file.parent_path().string());
 
-    if (! output_path.empty()) {
+    wxFileDialog dlg(this, (printer_technology() == ptFFF) ? _(L("Save G-code file as:")) : _(L("Save Zip file as:")),
+        start_dir,
+        from_path(default_output_file.filename()),
+        GUI::file_wildcards((printer_technology() == ptFFF) ? FT_GCODE : FT_PNGZIP, default_output_file.extension().string()),
+        wxFD_SAVE | wxFD_OVERWRITE_PROMPT
+    );
+
+    fs::path output_path;
+    if (dlg.ShowModal() == wxID_OK) {
+        fs::path path = into_path(dlg.GetPath());
+        wxGetApp().app_config->update_last_output_dir(path.parent_path().string());
+        output_path = std::move(path);
+    }
+    if (! output_path.empty())
         p->export_gcode(std::move(output_path), PrintHostJob());
-    }
 }
 
 void Plater::export_stl(bool selection_only)
@@ -2991,7 +2967,12 @@ void Plater::send_gcode()
     // Obtain default output path
     fs::path default_output_file;
     try {
-        default_output_file = this->p->background_process.current_print()->output_filepath("");
+		// Update the background processing, so that the placeholder parser will get the correct values for the ouput file template.
+		// Also if there is something wrong with the current configuration, a pop-up dialog will be shown and the export will not be performed.
+		unsigned int state = this->p->update_restart_background_process(false, false);
+		if (state & priv::UPDATE_BACKGROUND_PROCESS_INVALID)
+			return;
+		default_output_file = this->p->background_process.current_print()->output_filepath("");
     } catch (const std::exception &ex) {
         show_error(this, ex.what());
         return;
diff --git a/src/slic3r/GUI/Plater.hpp b/src/slic3r/GUI/Plater.hpp
index 09b7348d5..e3601b65c 100644
--- a/src/slic3r/GUI/Plater.hpp
+++ b/src/slic3r/GUI/Plater.hpp
@@ -140,8 +140,7 @@ public:
 
     void cut(size_t obj_idx, size_t instance_idx, coordf_t z, bool keep_upper = true, bool keep_lower = true, bool rotate_lower = false);
 
-    // Note: empty path means "use the default"
-    void export_gcode(boost::filesystem::path output_path = boost::filesystem::path());
+    void export_gcode();
     void export_stl(bool selection_only = false);
     void export_amf();
     void export_3mf(const boost::filesystem::path& output_path = boost::filesystem::path());
diff --git a/src/slic3r/GUI/Preset.cpp b/src/slic3r/GUI/Preset.cpp
index 53650481c..871cd0b73 100644
--- a/src/slic3r/GUI/Preset.cpp
+++ b/src/slic3r/GUI/Preset.cpp
@@ -517,16 +517,6 @@ void PresetCollection::add_default_preset(const std::vector<std::string> &keys,
     ++ m_num_default_presets;
 }
 
-bool is_file_plain(const std::string &path)
-{
-#ifdef _MSC_VER
-    DWORD attributes = GetFileAttributesW(boost::nowide::widen(path).c_str());
-    return (attributes & (FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_SYSTEM)) == 0;
-#else
-    return true;
-#endif
-}
-
 // Load all presets found in dir_path.
 // Throws an exception on error.
 void PresetCollection::load_presets(const std::string &dir_path, const std::string &subdir)
@@ -538,10 +528,7 @@ void PresetCollection::load_presets(const std::string &dir_path, const std::stri
 	// (see the "Preset already present, not loading" message).
 	std::deque<Preset> presets_loaded;
 	for (auto &dir_entry : boost::filesystem::directory_iterator(dir))
-        if (boost::filesystem::is_regular_file(dir_entry.status()) && boost::algorithm::iends_with(dir_entry.path().filename().string(), ".ini") &&
-            // Ignore system and hidden files, which may be created by the DropBox synchronisation process.
-            // https://github.com/prusa3d/Slic3r/issues/1298
-            is_file_plain(dir_entry.path().string())) {
+        if (Slic3r::is_ini_file(dir_entry)) {
             std::string name = dir_entry.path().filename().string();
             // Remove the .ini suffix.
             name.erase(name.size() - 4);
@@ -1169,6 +1156,18 @@ std::string PresetCollection::name() const
     }
 }
 
+std::string PresetCollection::section_name() const
+{
+    switch (this->type()) {
+    case Preset::TYPE_PRINT:        return "print";
+    case Preset::TYPE_FILAMENT:     return "filament";
+    case Preset::TYPE_SLA_PRINT:    return "sla_print";
+    case Preset::TYPE_SLA_MATERIAL: return "sla_material";
+    case Preset::TYPE_PRINTER:      return "printer";
+    default:                        return "invalid";
+    }
+}
+
 std::vector<std::string> PresetCollection::system_preset_names() const
 {
     size_t num = 0;
diff --git a/src/slic3r/GUI/Preset.hpp b/src/slic3r/GUI/Preset.hpp
index eae406bef..73a921cf7 100644
--- a/src/slic3r/GUI/Preset.hpp
+++ b/src/slic3r/GUI/Preset.hpp
@@ -230,7 +230,10 @@ public:
     void            reset(bool delete_files);
 
     Preset::Type    type() const { return m_type; }
+    // Name, to be used on the screen and in error messages. Not localized.
     std::string     name() const;
+    // Name, to be used as a section name in config bundle, and as a folder name for presets.
+    std::string     section_name() const;
     const std::deque<Preset>& operator()() const { return m_presets; }
 
     // Add default preset at the start of the collection, increment the m_default_preset counter.
diff --git a/src/slic3r/GUI/PresetBundle.cpp b/src/slic3r/GUI/PresetBundle.cpp
index 4c6c52763..5f33fd00a 100644
--- a/src/slic3r/GUI/PresetBundle.cpp
+++ b/src/slic3r/GUI/PresetBundle.cpp
@@ -243,7 +243,7 @@ std::string PresetBundle::load_system_presets()
     std::string errors_cummulative;
     bool        first = true;
     for (auto &dir_entry : boost::filesystem::directory_iterator(dir))
-        if (boost::filesystem::is_regular_file(dir_entry.status()) && boost::algorithm::iends_with(dir_entry.path().filename().string(), ".ini")) {
+        if (Slic3r::is_ini_file(dir_entry)) {
             std::string name = dir_entry.path().filename().string();
             // Remove the .ini suffix.
             name.erase(name.size() - 4);
@@ -1208,7 +1208,7 @@ size_t PresetBundle::load_configbundle(const std::string &path, unsigned int fla
 #else
                 // Store the print/filament/printer presets at the same location as the upstream Slic3r.
 #endif
-                / presets->name() / file_name).make_preferred();
+                / presets->section_name() / file_name).make_preferred();
             // Load the preset into the list of presets, save it to disk.
             Preset &loaded = presets->load_preset(file_path.string(), preset_name, std::move(config), false);
             if (flags & LOAD_CFGBNDLE_SAVE)
@@ -1365,7 +1365,7 @@ void PresetBundle::export_configbundle(const std::string &path, bool export_syst
             if (preset.is_default || preset.is_external || (preset.is_system && ! export_system_settings))
                 // Only export the common presets, not external files or the default preset.
                 continue;
-            c << std::endl << "[" << presets->name() << ":" << preset.name << "]" << std::endl;
+            c << std::endl << "[" << presets->section_name() << ":" << preset.name << "]" << std::endl;
             for (const std::string &opt_key : preset.config.keys())
                 c << opt_key << " = " << preset.config.serialize(opt_key) << std::endl;
         }
diff --git a/src/slic3r/Utils/FixModelByWin10.cpp b/src/slic3r/Utils/FixModelByWin10.cpp
index 4b487588a..1daeaff26 100644
--- a/src/slic3r/Utils/FixModelByWin10.cpp
+++ b/src/slic3r/Utils/FixModelByWin10.cpp
@@ -216,7 +216,7 @@ void fix_model_by_win10_sdk(const std::string &path_src, const std::string &path
 
 	HRESULT hr = (*s_RoInitialize)(RO_INIT_MULTITHREADED);
 	{
-		on_progress(L("Exporting the source model"), 20);
+		on_progress(L("Exporting source model"), 20);
 
 		Microsoft::WRL::ComPtr<ABI::Windows::Storage::Streams::IRandomAccessStream>       fileStream;
 		hr = winrt_open_file_stream(boost::nowide::widen(path_src), ABI::Windows::Storage::FileAccessMode::FileAccessMode_Read, fileStream.GetAddressOf(), throw_on_cancel);
@@ -239,7 +239,7 @@ void fix_model_by_win10_sdk(const std::string &path_src, const std::string &path
 		unsigned num_meshes = 0;
 		hr = meshes->get_Size(&num_meshes);
 		
-		on_progress(L("Repairing the model by the Netfabb service"), 40);
+		on_progress(L("Repairing model by the Netfabb service"), 40);
 		
 		Microsoft::WRL::ComPtr<ABI::Windows::Foundation::IAsyncAction>					  repairAsync;
 		hr = model->RepairAsync(repairAsync.GetAddressOf());
@@ -248,7 +248,7 @@ void fix_model_by_win10_sdk(const std::string &path_src, const std::string &path
 			throw std::runtime_error(L("Mesh repair failed."));
 		repairAsync->GetResults();
 
-		on_progress(L("Loading the repaired model"), 60);
+		on_progress(L("Loading repaired model"), 60);
 
 		// Verify the number of meshes returned after the repair action.
 		meshes.Reset();
@@ -316,7 +316,7 @@ public:
    const char* what() const throw() { return "Model repair has been canceled"; }
 };
 
-void fix_model_by_win10_sdk_gui(const ModelObject &model_object, const Print &print, Model &result)
+void fix_model_by_win10_sdk_gui(ModelObject &model_object, int volume_idx)
 {
 	std::mutex 						mutex;
 	std::condition_variable			condition;
@@ -329,6 +329,12 @@ void fix_model_by_win10_sdk_gui(const ModelObject &model_object, const Print &pr
 	std::atomic<bool>				canceled = false;
 	std::atomic<bool>				finished = false;
 
+	std::vector<ModelVolume*> volumes;
+	if (volume_idx == -1)
+		volumes = model_object.volumes;
+	else
+		volumes.emplace_back(model_object.volumes[volume_idx]);
+
 	// Open a progress dialog.
 	wxProgressDialog progress_dialog(
 		_(L("Model fixing")),
@@ -336,43 +342,64 @@ void fix_model_by_win10_sdk_gui(const ModelObject &model_object, const Print &pr
 		100, nullptr, wxPD_AUTO_HIDE | wxPD_APP_MODAL | wxPD_CAN_ABORT);
 	// Executing the calculation in a background thread, so that the COM context could be created with its own threading model.
 	// (It seems like wxWidgets initialize the COM contex as single threaded and we need a multi-threaded context).
-	bool success  = false;
-	auto on_progress = [&mutex, &condition, &progress](const char *msg, unsigned prcnt) {
+	bool   success = false;
+	size_t ivolume = 0;
+	auto on_progress = [&mutex, &condition, &ivolume, &volumes, &progress](const char *msg, unsigned prcnt) {
         std::lock_guard<std::mutex> lk(mutex);
 		progress.message = msg;
-		progress.percent = prcnt;
+		progress.percent = (int)floor((float(prcnt) + float(ivolume) * 100.f) / float(volumes.size()));
 		progress.updated = true;
 	    condition.notify_all();
 	};
-	auto worker_thread = boost::thread([&model_object, &print, &result, on_progress, &success, &canceled, &finished]() {
+	auto worker_thread = boost::thread([&model_object, &volumes, &ivolume, on_progress, &success, &canceled, &finished]() {
 		try {
-			on_progress(L("Exporting the source model"), 0);
-			boost::filesystem::path path_src = boost::filesystem::temp_directory_path() / boost::filesystem::unique_path();
-			path_src += ".3mf";
-			Model model;
-            DynamicPrintConfig config;
-			model.add_object(model_object);
-			if (! Slic3r::store_3mf(path_src.string().c_str(), &model, &config)) {
+			std::vector<TriangleMesh> meshes_repaired;
+			meshes_repaired.reserve(volumes.size());
+			for (; ivolume < volumes.size(); ++ ivolume) {
+				on_progress(L("Exporting source model"), 0);
+				boost::filesystem::path path_src = boost::filesystem::temp_directory_path() / boost::filesystem::unique_path();
+				path_src += ".3mf";
+				Model model;
+				ModelObject *model_object = model.add_object();
+				model_object->add_volume(*volumes[ivolume]);
+				model_object->add_instance();
+				if (! Slic3r::store_3mf(path_src.string().c_str(), &model, nullptr)) {
+					boost::filesystem::remove(path_src);
+					throw std::runtime_error(L("Export of a temporary 3mf file failed"));
+				}
+				model.clear_objects();
+				model.clear_materials();
+				boost::filesystem::path path_dst = boost::filesystem::temp_directory_path() / boost::filesystem::unique_path();
+				path_dst += ".3mf";
+				fix_model_by_win10_sdk(path_src.string().c_str(), path_dst.string(), on_progress, 
+					[&canceled]() { if (canceled) throw RepairCanceledException(); });
 				boost::filesystem::remove(path_src);
-				throw std::runtime_error(L("Export of a temporary 3mf file failed"));
+	            // PresetBundle bundle;
+				on_progress(L("Loading repaired model"), 80);
+				DynamicPrintConfig config;
+				bool loaded = Slic3r::load_3mf(path_dst.string().c_str(), &config, &model);
+			    boost::filesystem::remove(path_dst);
+				if (! loaded)
+	 				throw std::runtime_error(L("Import of the repaired 3mf file failed"));
+	 			if (model.objects.size() == 0)
+	 				throw std::runtime_error(L("Repaired 3MF file does not contain any object"));
+	 			if (model.objects.size() > 1)
+	 				throw std::runtime_error(L("Repaired 3MF file contains more than one object"));
+	 			if (model.objects.front()->volumes.size() == 0)
+	 				throw std::runtime_error(L("Repaired 3MF file does not contain any volume"));
+				if (model.objects.front()->volumes.size() > 1)
+	 				throw std::runtime_error(L("Repaired 3MF file contains more than one volume"));
+	 			meshes_repaired.emplace_back(std::move(model.objects.front()->volumes.front()->mesh));
 			}
-			model.clear_objects(); 
-			model.clear_materials();
-			boost::filesystem::path path_dst = boost::filesystem::temp_directory_path() / boost::filesystem::unique_path();
-			path_dst += ".3mf";
-			fix_model_by_win10_sdk(path_src.string().c_str(), path_dst.string(), on_progress, 
-				[&canceled]() { if (canceled) throw RepairCanceledException(); });
-			boost::filesystem::remove(path_src);
-            // PresetBundle bundle;
-			on_progress(L("Loading the repaired model"), 80);
-            bool loaded = Slic3r::load_3mf(path_dst.string().c_str(), &config, &result);
-            result.objects[0]->name = boost::filesystem::path(model_object.name).filename().stem().string() + "_fixed";
-		    boost::filesystem::remove(path_dst);
-			if (! loaded)
- 				throw std::runtime_error(L("Import of the repaired 3mf file failed"));
+			for (size_t i = 0; i < volumes.size(); ++ i) {
+				volumes[i]->mesh = std::move(meshes_repaired[i]);
+				volumes[i]->set_new_unique_id();
+			}
+			model_object.invalidate_bounding_box();
+			-- ivolume;
+			on_progress(L("Model repair finished"), 100);
 			success  = true;
 			finished = true;
-			on_progress(L("Model repair finished"), 100);
 		} catch (RepairCanceledException & /* ex */) {
 			canceled = true;
 			finished = true;
diff --git a/src/slic3r/Utils/FixModelByWin10.hpp b/src/slic3r/Utils/FixModelByWin10.hpp
index c148a6970..8e4766467 100644
--- a/src/slic3r/Utils/FixModelByWin10.hpp
+++ b/src/slic3r/Utils/FixModelByWin10.hpp
@@ -12,12 +12,12 @@ class Print;
 #ifdef HAS_WIN10SDK
 
 extern bool is_windows10();
-extern void fix_model_by_win10_sdk_gui(const ModelObject &model_object, const Print &print, Model &result);
+extern void fix_model_by_win10_sdk_gui(ModelObject &model_object, int volume_idx);
 
 #else /* HAS_WIN10SDK */
 
 inline bool is_windows10() { return false; }
-inline void fix_model_by_win10_sdk_gui(const ModelObject &, const Print &, Model &) {}
+inline void fix_model_by_win10_sdk_gui(ModelObject &, int) {}
 
 #endif /* HAS_WIN10SDK */
 
diff --git a/src/slic3r/Utils/PresetUpdater.cpp b/src/slic3r/Utils/PresetUpdater.cpp
index bfa3af3e6..a22d463fb 100644
--- a/src/slic3r/Utils/PresetUpdater.cpp
+++ b/src/slic3r/Utils/PresetUpdater.cpp
@@ -180,12 +180,11 @@ bool PresetUpdater::priv::get_file(const std::string &url, const fs::path &targe
 // Remove leftover paritally downloaded files, if any.
 void PresetUpdater::priv::prune_tmps() const
 {
-	for (fs::directory_iterator it(cache_path); it != fs::directory_iterator(); ++it) {
-		if (it->path().extension() == TMP_EXTENSION) {
-			BOOST_LOG_TRIVIAL(debug) << "Cache prune: " << it->path().string();
-			fs::remove(it->path());
+    for (auto &dir_entry : boost::filesystem::directory_iterator(cache_path))
+		if (is_plain_file(dir_entry) && dir_entry.path().extension() == TMP_EXTENSION) {
+			BOOST_LOG_TRIVIAL(debug) << "Cache prune: " << dir_entry.path().string();
+			fs::remove(dir_entry.path());
 		}
-	}
 }
 
 // Get Slic3rPE version available online, save in AppConfig.
@@ -299,9 +298,9 @@ void PresetUpdater::priv::check_install_indices() const
 {
 	BOOST_LOG_TRIVIAL(info) << "Checking if indices need to be installed from resources...";
 
-	for (fs::directory_iterator it(rsrc_path); it != fs::directory_iterator(); ++it) {
-		const auto &path = it->path();
-		if (path.extension() == ".idx") {
+    for (auto &dir_entry : boost::filesystem::directory_iterator(rsrc_path))
+		if (is_idx_file(dir_entry)) {
+			const auto &path = dir_entry.path();
 			const auto path_in_cache = cache_path / path.filename();
 
 			if (! fs::exists(path_in_cache)) {
@@ -318,7 +317,6 @@ void PresetUpdater::priv::check_install_indices() const
 				}
 			}
 		}
-	}
 }
 
 // Generates a list of bundle updates that are to be performed