diff --git a/src/libslic3r/AppConfig.cpp b/src/libslic3r/AppConfig.cpp
index 503ebd24f..a7d2953dc 100644
--- a/src/libslic3r/AppConfig.cpp
+++ b/src/libslic3r/AppConfig.cpp
@@ -127,6 +127,12 @@ void AppConfig::set_defaults()
 
         if (get("default_action_on_select_preset").empty())
             set("default_action_on_select_preset", "none");     // , "transfer", "discard" or "save" 
+
+        if (get("default_action_preset_on_new_project").empty())
+            set("default_action_preset_on_new_project", "1");
+
+        if (get("default_action_on_new_project").empty())
+            set("default_action_on_new_project", "1");
     }
 #if ENABLE_CUSTOMIZABLE_FILES_ASSOCIATION_ON_WIN
     else {
diff --git a/src/libslic3r/Config.hpp b/src/libslic3r/Config.hpp
index bd7c32f8e..e9735fd19 100644
--- a/src/libslic3r/Config.hpp
+++ b/src/libslic3r/Config.hpp
@@ -1834,7 +1834,7 @@ public:
     // An UnknownOptionException is thrown in case some option keys are not defined by this->def(),
     // or this ConfigBase is of a StaticConfig type and it does not support some of the keys, and ignore_nonexistent is not set.
     void apply_only(const ConfigBase &other, const t_config_option_keys &keys, bool ignore_nonexistent = false);
-    bool equals(const ConfigBase &other) const { return this->diff(other).empty(); }
+    bool equals(const ConfigBase &other) const { return this->keys().size() == other.keys().size() && this->diff(other).empty(); }
     t_config_option_keys diff(const ConfigBase &other) const;
     t_config_option_keys equal(const ConfigBase &other) const;
     std::string opt_serialize(const t_config_option_key &opt_key) const;
diff --git a/src/libslic3r/Format/3mf.cpp b/src/libslic3r/Format/3mf.cpp
index e4d07a211..234123fa8 100644
--- a/src/libslic3r/Format/3mf.cpp
+++ b/src/libslic3r/Format/3mf.cpp
@@ -2097,7 +2097,7 @@ namespace Slic3r {
             return false;
         }
 
-        if ((thumbnail_data != nullptr) && thumbnail_data->is_valid())
+        if (!model.objects.empty() && thumbnail_data != nullptr && thumbnail_data->is_valid())
         {
             // Adds the file Metadata/thumbnail.png.
             if (!_add_thumbnail_file_to_archive(archive, *thumbnail_data))
@@ -2121,12 +2121,13 @@ namespace Slic3r {
         // Adds model file ("3D/3dmodel.model").
         // This is the one and only file that contains all the geometry (vertices and triangles) of all ModelVolumes.
         IdToObjectDataMap objects_data;
-        if (!_add_model_file_to_archive(filename, archive, model, objects_data))
-        {
-            close_zip_writer(&archive);
-            boost::filesystem::remove(filename);
-            return false;
-        }
+        if(!model.objects.empty())
+            if (!_add_model_file_to_archive(filename, archive, model, objects_data))
+            {
+                close_zip_writer(&archive);
+                boost::filesystem::remove(filename);
+                return false;
+            }
 
         // Adds layer height profile file ("Metadata/Slic3r_PE_layer_heights_profile.txt").
         // All layer height profiles of all ModelObjects are stored here, indexed by 1 based index of the ModelObject in Model.
diff --git a/src/libslic3r/Geometry.cpp b/src/libslic3r/Geometry.cpp
index 24530269d..1f38e3b94 100644
--- a/src/libslic3r/Geometry.cpp
+++ b/src/libslic3r/Geometry.cpp
@@ -1185,6 +1185,16 @@ Transformation Transformation::operator * (const Transformation& other) const
     return Transformation(get_matrix() * other.get_matrix());
 }
 
+
+bool Transformation::operator==(const Transformation& other) const
+{
+    return m_offset == other.m_offset
+        && m_rotation == other.m_rotation
+        && m_scaling_factor == other.m_scaling_factor
+        && m_mirror == other.m_mirror
+        && m_matrix.isApprox(other.m_matrix);
+}
+
 Transformation Transformation::volume_to_bed_transformation(const Transformation& instance_transformation, const BoundingBoxf3& bbox)
 {
     Transformation out;
diff --git a/src/libslic3r/Geometry.hpp b/src/libslic3r/Geometry.hpp
index 722cefa00..0429fe279 100644
--- a/src/libslic3r/Geometry.hpp
+++ b/src/libslic3r/Geometry.hpp
@@ -446,6 +446,8 @@ public:
     const Transform3d& get_matrix(bool dont_translate = false, bool dont_rotate = false, bool dont_scale = false, bool dont_mirror = false) const;
 
     Transformation operator * (const Transformation& other) const;
+    bool operator==(const Transformation& trsf) const;
+    bool operator!=(const Transformation& trsf) const { return !operator==(trsf); }
 
     // Find volume transformation, so that the chained (instance_trafo * volume_trafo) will be as close to identity
     // as possible in least squares norm in regard to the 8 corners of bbox.
diff --git a/src/libslic3r/Model.cpp b/src/libslic3r/Model.cpp
index d3d01c7f1..7246dde30 100644
--- a/src/libslic3r/Model.cpp
+++ b/src/libslic3r/Model.cpp
@@ -97,6 +97,30 @@ void Model::update_links_bottom_up_recursive()
 	}
 }
 
+bool Model::equals(const Model& rhs) const {
+    // check materials
+    if(this->materials.size() != rhs.materials.size())
+        return false;
+    for (const std::pair<const t_model_material_id, ModelMaterial*>& m : this->materials) {
+        // check the ID and m_model.
+        if (rhs.materials.find(m.first) == rhs.materials.end() || rhs.materials.at(m.first)->operator==(*m.second))
+            return false;
+    }
+    // check objects
+    if (this->objects.size() != rhs.objects.size())
+        return false;
+    for (int i = 0; i < rhs.objects.size(); i++) {
+        // Copy including the ID, leave ID set to invalid (zero).
+        if (rhs.objects[i]->equals(*objects[i]))
+            return false;
+    }
+
+    // copy custom code per height
+    if (this->custom_gcode_per_print_z != rhs.custom_gcode_per_print_z)
+            return false;
+    return true;
+}
+
 Model Model::read_from_file(const std::string& input_file, DynamicPrintConfig* config, bool add_default_instances, bool check_version)
 {
     Model model;
@@ -152,8 +176,9 @@ Model Model::read_from_archive(const std::string& input_file, DynamicPrintConfig
     if (!result)
         throw Slic3r::RuntimeError("Loading of a model file failed.");
 
-    if (model.objects.empty())
-        throw Slic3r::RuntimeError("The supplied file couldn't be read because it's empty");
+    //it can read the config only
+    //if (model.objects.empty())
+        //throw Slic3r::RuntimeError("The supplied file couldn't be read because it's empty");
 
     for (ModelObject *o : model.objects)
     {
@@ -614,6 +639,33 @@ void ModelObject::assign_new_unique_ids_recursive()
     this->layer_height_profile.set_new_unique_id();
 }
 
+bool ModelObject::equals(const ModelObject& rhs) {
+
+    if (this->id() != rhs.id() || this->config.id() != rhs.config.id()) return false;
+
+    if (this->name != rhs.name) return false;
+    if (this->input_file != rhs.input_file) return false;
+    // Copies the config's ID
+    if (this->config != rhs.config) return false;
+    if (this->sla_support_points != rhs.sla_support_points) return false;
+    if (this->sla_points_status != rhs.sla_points_status) return false;
+    if (this->sla_drain_holes != rhs.sla_drain_holes) return false;
+    if (this->layer_config_ranges != rhs.layer_config_ranges) return false;
+    if (this->layer_height_profile != rhs.layer_height_profile) return false;
+    if (this->printable != rhs.printable) return false;
+    if (this->origin_translation != rhs.origin_translation) return false;
+    if (m_bounding_box != rhs.m_bounding_box) return false;
+    if (m_bounding_box_valid != rhs.m_bounding_box_valid) return false;
+    if (m_raw_bounding_box != rhs.m_raw_bounding_box) return false;
+    if (m_raw_bounding_box_valid != rhs.m_raw_bounding_box_valid) return false;
+    if (m_raw_mesh_bounding_box != rhs.m_raw_mesh_bounding_box) return false;
+    if (m_raw_mesh_bounding_box_valid != rhs.m_raw_mesh_bounding_box_valid) return false;
+
+    if (this->volumes != rhs.volumes) return false;
+    if (this->instances != rhs.instances) return false;
+    return true;
+}
+
 // Clone this ModelObject including its volumes and instances, keep the IDs of the copies equal to the original.
 // Called by Print::apply() to clone the Model / ModelObject hierarchy to the back end for background processing.
 //ModelObject* ModelObject::clone(Model *parent)
@@ -1824,6 +1876,14 @@ void ModelVolume::convert_from_imperial_units()
     this->source.is_converted_from_inches = true;
 }
 
+bool ModelVolume::operator!=(const ModelVolume& mm) const
+{
+    if (object->id() != mm.object->id()) return false;
+    if (m_type != mm.m_type || m_material_id != mm.m_material_id) return false;
+    if (m_transformation != mm.m_transformation) return false;
+    return true;
+}
+
 void ModelInstance::transform_mesh(TriangleMesh* mesh, bool dont_translate) const
 {
     mesh->transform(get_matrix(dont_translate));
@@ -1874,6 +1934,9 @@ void ModelInstance::transform_polygon(Polygon* polygon) const
     polygon->scale(get_scaling_factor(X), get_scaling_factor(Y)); // scale around polygon origin
 }
 
+bool ModelInstance::operator==(const ModelInstance& other) const {
+    return m_transformation == other.m_transformation && print_volume_state == other.print_volume_state && printable == other.printable;
+}
 
 arrangement::ArrangePolygon ModelInstance::get_arrange_polygon() const
 {
@@ -1903,6 +1966,8 @@ arrangement::ArrangePolygon ModelInstance::get_arrange_polygon() const
     return ret;
 }
 
+
+
 indexed_triangle_set FacetsAnnotation::get_facets(const ModelVolume& mv, EnforcerBlockerType type) const
 {
     TriangleSelector selector(mv.mesh());
diff --git a/src/libslic3r/Model.hpp b/src/libslic3r/Model.hpp
index 235bfc258..b1b86f4a6 100644
--- a/src/libslic3r/Model.hpp
+++ b/src/libslic3r/Model.hpp
@@ -146,6 +146,9 @@ public:
     void apply(const t_model_material_attributes &attributes)
         { this->attributes.insert(attributes.begin(), attributes.end()); }
 
+    bool operator==(const ModelMaterial& mm) const { return attributes == mm.attributes && config == mm.config; }
+    bool operator!=(const ModelMaterial& mm) const { return !operator==(mm); }
+
 private:
     // Parent, owning this material.
     Model *m_model;
@@ -194,6 +197,10 @@ public:
         ar(cereal::base_class<ObjectWithTimestamp>(this), m_data);
     }
 
+
+    bool                  operator==(const LayerHeightProfile& other) const { return object_id_and_timestamp_match(other) && m_data == other.m_data; }
+    bool                  operator!=(const LayerHeightProfile& other) const { return !this->operator==(other); }
+
 private:
     // Constructors to be only called by derived classes.
     // Default constructor to assign a unique ID.
@@ -282,6 +289,8 @@ public:
     const BoundingBoxf3& bounding_box() const;
     void invalidate_bounding_box() { m_bounding_box_valid = false; m_raw_bounding_box_valid = false; m_raw_mesh_bounding_box_valid = false; }
 
+    bool equals(const ModelObject &other);
+
     // A mesh containing all transformed instances of this object.
     TriangleMesh mesh() const;
     // Non-transformed (non-rotated, non-scaled, non-translated) sum of non-modifier object volumes.
@@ -670,6 +679,8 @@ public:
         this->seam_facets.set_new_unique_id();
     }
 
+    bool operator!=(const ModelVolume& mm) const;
+
 protected:
 	friend class Print;
     friend class SLAPrint;
@@ -677,7 +688,7 @@ protected:
 	friend class ModelObject;
 
 	// Copies IDs of both the ModelVolume and its config.
-	explicit ModelVolume(const ModelVolume &rhs) = default;
+    explicit ModelVolume(const ModelVolume& rhs) = default;
     void     set_model_object(ModelObject *model_object) { object = model_object; }
 	void 	 assign_new_unique_ids_recursive() override;
     void     transform_this_mesh(const Transform3d& t, bool fix_left_handed);
@@ -888,6 +899,9 @@ public:
         this->object->invalidate_bounding_box();
     }
 
+    bool operator==(const ModelInstance& other) const;
+    bool operator!=(const ModelInstance& other) const { return !operator==(other); }
+
 protected:
     friend class Print;
     friend class SLAPrint;
@@ -985,6 +999,8 @@ public:
     static Model read_from_file(const std::string& input_file, DynamicPrintConfig* config = nullptr, bool add_default_instances = true, bool check_version = false);
     static Model read_from_archive(const std::string& input_file, DynamicPrintConfig* config, bool add_default_instances = true, bool check_version = false);
 
+    bool equals(const Model& rhs) const;
+
     // Add a new ModelObject to this Model, generate a new ID for this ModelObject.
     ModelObject* add_object();
     ModelObject* add_object(const char *name, const char *path, const TriangleMesh &mesh);
diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index eb2ecd00d..df8e1a126 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -1369,7 +1369,7 @@ void PrintConfigDef::init_fff_params()
     def->sidetext = L("mm/s");
     def->min = 0;
     def->mode = comExpert;
-    def->set_default_value(new ConfigOptionFloats { 2.2f });
+    def->set_default_value(new ConfigOptionFloats { 2.2 });
 
     def = this->add("filament_minimal_purge_on_wipe_tower", coFloats);
     def->label = L("Minimal purge on wipe tower");
@@ -1380,7 +1380,7 @@ void PrintConfigDef::init_fff_params()
     def->sidetext = L("mm³");
     def->min = 0;
     def->mode = comExpert;
-    def->set_default_value(new ConfigOptionFloats { 15.f });
+    def->set_default_value(new ConfigOptionFloats { 15. });
 
     def = this->add("filament_cooling_final_speed", coFloats);
     def->label = L("Speed of the last cooling move");
@@ -1388,7 +1388,7 @@ void PrintConfigDef::init_fff_params()
     def->sidetext = L("mm/s");
     def->min = 0;
     def->mode = comExpert;
-    def->set_default_value(new ConfigOptionFloats { 3.4f });
+    def->set_default_value(new ConfigOptionFloats { 3.4 });
 
     def = this->add("filament_load_time", coFloats);
     def->label = L("Filament load time");
@@ -1396,7 +1396,7 @@ void PrintConfigDef::init_fff_params()
     def->sidetext = L("s");
     def->min = 0;
     def->mode = comExpert;
-    def->set_default_value(new ConfigOptionFloats { 0.0f });
+    def->set_default_value(new ConfigOptionFloats { 0.0 });
 
     def = this->add("filament_ramming_parameters", coStrings);
     def->label = L("Ramming parameters");
@@ -1411,7 +1411,7 @@ void PrintConfigDef::init_fff_params()
     def->sidetext = L("s");
     def->min = 0;
     def->mode = comExpert;
-    def->set_default_value(new ConfigOptionFloats { 0.0f });
+    def->set_default_value(new ConfigOptionFloats { 0.0 });
 
     def = this->add("filament_diameter", coFloats);
     def->label = L("Diameter");
diff --git a/src/libslic3r/PrintConfig.hpp b/src/libslic3r/PrintConfig.hpp
index 0736c457b..fab0e1d50 100644
--- a/src/libslic3r/PrintConfig.hpp
+++ b/src/libslic3r/PrintConfig.hpp
@@ -1878,7 +1878,9 @@ public:
     auto                        cbegin() const { return m_data.cbegin(); }
     auto                        cend() const { return m_data.cend(); }
     t_config_option_keys        keys() const { return m_data.keys(); }
-    bool                        has(const t_config_option_key &opt_key) const { return m_data.has(opt_key); }
+    bool                        has(const t_config_option_key& opt_key) const { return m_data.has(opt_key); }
+    bool                        operator==(const ModelConfig& other) const { return m_data.equals(other.m_data); }
+    bool                        operator!=(const ModelConfig& other) const { return !this->operator==(other); }
     const ConfigOption*         option(const t_config_option_key &opt_key) const { return m_data.option(opt_key); }
     int                         opt_int(const t_config_option_key &opt_key) const { return m_data.opt_int(opt_key); }
     int                         extruder() const { return opt_int("extruder"); }
diff --git a/src/slic3r/GUI/CalibrationBedDialog.cpp b/src/slic3r/GUI/CalibrationBedDialog.cpp
index 5be7305cb..d0d1de8fd 100644
--- a/src/slic3r/GUI/CalibrationBedDialog.cpp
+++ b/src/slic3r/GUI/CalibrationBedDialog.cpp
@@ -33,7 +33,9 @@ void CalibrationBedDialog::create_buttons(wxStdDialogButtonSizer* buttons){
 void CalibrationBedDialog::create_geometry(wxCommandEvent& event_args) {
     Plater* plat = this->main_frame->plater();
     Model& model = plat->model();
-    plat->reset();
+    if (!plat->new_project("First layer calibration"))
+        return;
+
     bool autocenter = gui_app->app_config->get("autocenter") == "1";
     if(autocenter) {
         //disable aut-ocenter for this calibration.
diff --git a/src/slic3r/GUI/CalibrationBridgeDialog.cpp b/src/slic3r/GUI/CalibrationBridgeDialog.cpp
index 10e8d83ba..ba481cdd4 100644
--- a/src/slic3r/GUI/CalibrationBridgeDialog.cpp
+++ b/src/slic3r/GUI/CalibrationBridgeDialog.cpp
@@ -53,7 +53,8 @@ void CalibrationBridgeDialog::create_buttons(wxStdDialogButtonSizer* buttons){
 void CalibrationBridgeDialog::create_geometry(std::string setting_to_test, bool add) {
     Plater* plat = this->main_frame->plater();
     Model& model = plat->model();
-    plat->reset();
+    if (!plat->new_project("Bridge calibration"))
+        return;
 
     bool autocenter = gui_app->app_config->get("autocenter") == "1";
     if (autocenter) {
diff --git a/src/slic3r/GUI/CalibrationCubeDialog.cpp b/src/slic3r/GUI/CalibrationCubeDialog.cpp
index 93f72a7f9..f42cad315 100644
--- a/src/slic3r/GUI/CalibrationCubeDialog.cpp
+++ b/src/slic3r/GUI/CalibrationCubeDialog.cpp
@@ -54,7 +54,9 @@ void CalibrationCubeDialog::create_buttons(wxStdDialogButtonSizer* buttons){
 void CalibrationCubeDialog::create_geometry(std::string calibration_path) {
     Plater* plat = this->main_frame->plater();
     Model& model = plat->model();
-    plat->reset();
+    if (!plat->new_project("Calibration cube"))
+        return;
+
     std::vector<size_t> objs_idx = plat->load_files(std::vector<std::string>{
             Slic3r::resources_dir()+"/calibration/cube/"+ calibration_path}, true, false, false);
 
diff --git a/src/slic3r/GUI/CalibrationFlowDialog.cpp b/src/slic3r/GUI/CalibrationFlowDialog.cpp
index a254299a4..e48f9e6fc 100644
--- a/src/slic3r/GUI/CalibrationFlowDialog.cpp
+++ b/src/slic3r/GUI/CalibrationFlowDialog.cpp
@@ -38,7 +38,8 @@ void CalibrationFlowDialog::create_buttons(wxStdDialogButtonSizer* buttons){
 void CalibrationFlowDialog::create_geometry(float start, float delta) {
     Plater* plat = this->main_frame->plater();
     Model& model = plat->model();
-    plat->reset();
+    if (!plat->new_project("Flow calibration"))
+        return;
 
     bool autocenter = gui_app->app_config->get("autocenter") == "1";
     if (autocenter) {
diff --git a/src/slic3r/GUI/CalibrationOverBridgeDialog.cpp b/src/slic3r/GUI/CalibrationOverBridgeDialog.cpp
index 42f0d3fb2..80eade96c 100644
--- a/src/slic3r/GUI/CalibrationOverBridgeDialog.cpp
+++ b/src/slic3r/GUI/CalibrationOverBridgeDialog.cpp
@@ -43,7 +43,9 @@ void CalibrationOverBridgeDialog::create_geometry2(wxCommandEvent& event_args) {
 void CalibrationOverBridgeDialog::create_geometry(bool over_bridge) {
     Plater* plat = this->main_frame->plater();
     Model& model = plat->model();
-    plat->reset();
+    if (!plat->new_project("Over-bridge calibration"))
+        return;
+
     bool autocenter = gui_app->app_config->get("autocenter") == "1";
     if (autocenter) {
         //disable aut-ocenter for this calibration.
diff --git a/src/slic3r/GUI/CalibrationRetractionDialog.cpp b/src/slic3r/GUI/CalibrationRetractionDialog.cpp
index 902f24700..cbe9bf79d 100644
--- a/src/slic3r/GUI/CalibrationRetractionDialog.cpp
+++ b/src/slic3r/GUI/CalibrationRetractionDialog.cpp
@@ -100,7 +100,8 @@ void CalibrationRetractionDialog::remove_slowdown(wxCommandEvent& event_args) {
 void CalibrationRetractionDialog::create_geometry(wxCommandEvent& event_args) {
     Plater* plat = this->main_frame->plater();
     Model& model = plat->model();
-    plat->reset();
+    if (!plat->new_project("Retraction calibration"))
+        return;
 
     bool autocenter = gui_app->app_config->get("autocenter") == "1";
     if (autocenter) {
diff --git a/src/slic3r/GUI/CalibrationTempDialog.cpp b/src/slic3r/GUI/CalibrationTempDialog.cpp
index e485e8270..f0941f4b1 100644
--- a/src/slic3r/GUI/CalibrationTempDialog.cpp
+++ b/src/slic3r/GUI/CalibrationTempDialog.cpp
@@ -56,7 +56,9 @@ void CalibrationTempDialog::create_buttons(wxStdDialogButtonSizer* buttons){
 void CalibrationTempDialog::create_geometry(wxCommandEvent& event_args) {
     Plater* plat = this->main_frame->plater();
     Model& model = plat->model();
-    plat->reset();
+    if (!plat->new_project("Temperature calibration"))
+        return;
+
     std::vector<size_t> objs_idx = plat->load_files(std::vector<std::string>{
             Slic3r::resources_dir()+"/calibration/filament_temp/Smart_compact_temperature_calibration_item.amf"}, true, false, false);
 
diff --git a/src/slic3r/GUI/FreeCADDialog.cpp b/src/slic3r/GUI/FreeCADDialog.cpp
index 87356dc04..2fe699672 100644
--- a/src/slic3r/GUI/FreeCADDialog.cpp
+++ b/src/slic3r/GUI/FreeCADDialog.cpp
@@ -1026,7 +1026,7 @@ void FreeCADDialog::create_geometry(wxCommandEvent& event_args) {
     Plater* plat = this->main_frame->plater();
     Model& model = plat->model();
     if(cmb_add_replace->GetSelection() == 0)
-        plat->reset();
+        plat->new_project();
     std::vector<size_t> objs_idx = plat->load_files(std::vector<std::string>{ object_path.generic_string() }, true, false, false);
     if (objs_idx.empty()) return;
     //don't save in the temp directory: erase the link to it
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 9ef72c147..8400d1259 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -4511,7 +4511,7 @@ bool GLCanvas3D::_init_main_toolbar()
     item.tooltip = _utf8(L("Delete all")) + " [" + GUI::shortkey_ctrl_prefix() + "Del]";
     item.sprite_id = 2;
     item.left.action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_DELETE_ALL)); };
-    item.enabling_callback = []()->bool { return wxGetApp().plater()->can_delete_all(); };
+    item.enabling_callback = []()->bool { return wxGetApp().plater()/*->can_delete_all()*/; };
     if (!m_main_toolbar.add_item(item))
         return false;
 
diff --git a/src/slic3r/GUI/MainFrame.cpp b/src/slic3r/GUI/MainFrame.cpp
index 6f945fc04..04abc8488 100644
--- a/src/slic3r/GUI/MainFrame.cpp
+++ b/src/slic3r/GUI/MainFrame.cpp
@@ -208,6 +208,10 @@ DPIFrame(NULL, wxID_ANY, "", wxDefaultPosition, wxDefaultSize, wxDEFAULT_FRAME_S
             event.Veto();
             return;
         }
+        if (event.CanVeto() && plater() && !plater()->check_project_unsaved_changes()) {
+            event.Veto();
+            return;
+        }
         if (event.CanVeto() && !wxGetApp().check_print_host_queue()) {
             event.Veto();
             return;
@@ -486,12 +490,18 @@ void MainFrame::shutdown()
 void MainFrame::update_title()
 {
     wxString title = wxEmptyString;
+    bool has_name = false;
     if (m_plater != nullptr) {
         // m_plater->get_project_filename() produces file name including path, but excluding extension.
         // Don't try to remove the extension, it would remove part of the file name after the last dot!
         wxString project = from_path(into_path(m_plater->get_project_filename()).filename());
-        if (!project.empty())
+        if (project.empty()) {
+            project = m_plater->get_project_filename();
+        }
+        if (!project.empty()) {
+            has_name = true;
             title += (project + " - ");
+        }
     }
 
     std::string build_id = wxGetApp().is_editor() ? SLIC3R_BUILD_ID : GCODEVIEWER_BUILD_ID;
@@ -511,7 +521,7 @@ void MainFrame::update_title()
     }
 
     title += wxString(SLIC3R_APP_NAME) + "_" + wxString(SLIC3R_VERSION) ;
-    if (wxGetApp().is_editor())
+    if (wxGetApp().is_editor() && !has_name)
         title += (" " + _L("based on PrusaSlicer & Slic3r"));
 
     SetTitle(title);
@@ -664,12 +674,12 @@ bool MainFrame::is_active_and_shown_tab(Tab* tab)
 
 bool MainFrame::can_start_new_project() const
 {
-    return (m_plater != nullptr) && !m_plater->model().objects.empty();
+    return (m_plater != nullptr);
 }
 
 bool MainFrame::can_save() const
 {
-    return (m_plater != nullptr) && !m_plater->model().objects.empty();
+    return (m_plater != nullptr);
 }
 
 bool MainFrame::can_export_model() const
@@ -944,7 +954,7 @@ void MainFrame::init_menubar_as_editor()
     wxMenu* fileMenu = new wxMenu;
     {
         append_menu_item(fileMenu, wxID_ANY, _L("&New Project") + "\tCtrl+N", _L("Start a new project"),
-            [this](wxCommandEvent&) { if (m_plater) m_plater->new_project(); }, "", nullptr,
+            [this](wxCommandEvent&) { if (m_plater) m_plater->ask_for_new_project(); }, "", nullptr,
             [this](){return m_plater != nullptr && can_start_new_project(); }, this);
         append_menu_item(fileMenu, wxID_ANY, _L("&Open Project") + dots + "\tCtrl+O", _L("Open a project file"),
             [this](wxCommandEvent&) { if (m_plater) m_plater->load_project(); }, "open", nullptr,
@@ -986,14 +996,14 @@ void MainFrame::init_menubar_as_editor()
         Bind(wxEVT_UPDATE_UI, [this](wxUpdateUIEvent& evt) { evt.Enable(m_recent_projects.GetCount() > 0); }, recent_projects_submenu->GetId());
 
         append_menu_item(fileMenu, wxID_ANY, _L("&Save Project") + "\tCtrl+S", _L("Save current project file"),
-            [this](wxCommandEvent&) { if (m_plater) m_plater->export_3mf(into_path(m_plater->get_project_filename(".3mf"))); }, "save", nullptr,
+            [this](wxCommandEvent&) { if (m_plater) m_plater->save_project_as_3mf(into_path(m_plater->get_project_filename(".3mf"))); }, "save", nullptr,
             [this](){return m_plater != nullptr && can_save(); }, this);
 #ifdef __APPLE__
         append_menu_item(fileMenu, wxID_ANY, _L("Save Project &as") + dots + "\tCtrl+Shift+S", _L("Save current project file as"),
 #else
         append_menu_item(fileMenu, wxID_ANY, _L("Save Project &as") + dots + "\tCtrl+Alt+S", _L("Save current project file as"),
 #endif // __APPLE__
-            [this](wxCommandEvent&) { if (m_plater) m_plater->export_3mf(); }, "save", nullptr,
+            [this](wxCommandEvent&) { if (m_plater) m_plater->save_project_as_3mf(); }, "save", nullptr,
             [this](){return m_plater != nullptr && can_save(); }, this);
 
         fileMenu->AppendSeparator();
diff --git a/src/slic3r/GUI/OptionsGroup.cpp b/src/slic3r/GUI/OptionsGroup.cpp
index cb31e059c..403508917 100644
--- a/src/slic3r/GUI/OptionsGroup.cpp
+++ b/src/slic3r/GUI/OptionsGroup.cpp
@@ -634,8 +634,8 @@ void ConfigOptionsGroup::back_to_config_value(const DynamicPrintConfig& config,
 		value = get_config_value(config, opt_short_key, opt_index);
 	}
 
-	set_value(opt_key, value);
-	on_change_OG(opt_key, get_value(opt_key));
+    if(set_value(opt_key, value))
+        on_change_OG(opt_key, get_value(opt_key));
 }
 
 void ConfigOptionsGroup::on_kill_focus(const std::string& opt_key)
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index 082dd1a77..c67bd7d71 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -1777,8 +1777,9 @@ struct Plater::priv
     void select_all();
     void deselect_all();
     void remove(size_t obj_idx);
+    void remove_all();
     void delete_object_from_model(size_t obj_idx);
-    void reset();
+    void reset(std::string name = "");
     void mirror(Axis axis);
     void split_object();
     void split_volume();
@@ -1902,6 +1903,20 @@ struct Plater::priv
     // extension should contain the leading dot, i.e.: ".3mf"
     wxString get_project_filename(const wxString& extension = wxEmptyString) const;
     void set_project_filename(const wxString& filename);
+    void set_saved_project(const DynamicPrintConfig& config, const Model& model) { m_project_last_saved_cfg = config; m_saved_model = model; }
+    bool has_project_change(const DynamicPrintConfig& config, const Model& model) const {
+        if (m_project_last_saved_cfg.keys().empty()) {
+            //new project, unsaved
+            //check if current preset is dirty
+            PrinterTechnology printer_technology = wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology();
+            for (Tab* tab : wxGetApp().tabs_list)
+                if (tab->supports_printer_technology(printer_technology) && tab->current_preset_is_dirty()) {
+                    return false;
+                }
+        } else if(!m_project_last_saved_cfg.equals(config))
+            return false;
+        return !m_saved_model.equals(model);
+    }
 
     // Caching last value of show_action_buttons parameter for show_action_buttons(), so that a callback which does not know this state will not override it.
     mutable bool    			ready_to_slice = { false };
@@ -1928,6 +1943,8 @@ private:
 
     // path to project file stored with no extension
     wxString 					m_project_filename;
+    Model                       m_saved_model;
+    DynamicPrintConfig          m_project_last_saved_cfg;
     Slic3r::UndoRedo::Stack 	m_undo_redo_stack_main;
     Slic3r::UndoRedo::Stack 	m_undo_redo_stack_gizmos;
     Slic3r::UndoRedo::Stack    *m_undo_redo_stack_active = &m_undo_redo_stack_main;
@@ -2807,6 +2824,18 @@ void Plater::priv::remove(size_t obj_idx)
     object_list_changed();
 }
 
+void Plater::priv::remove_all()
+{
+    if (view3D->is_layers_editing_enabled())
+        view3D->enable_layers_editing(false);
+
+    model.clear_objects();
+    update();
+    // Delete object from Sidebar list. Do it after update, so that the GLScene selection is updated with the modified model.
+    sidebar->obj_list()->delete_all_objects_from_list();
+    object_list_changed();
+}
+
 
 void Plater::priv::delete_object_from_model(size_t obj_idx)
 {
@@ -2819,13 +2848,14 @@ void Plater::priv::delete_object_from_model(size_t obj_idx)
     object_list_changed();
 }
 
-void Plater::priv::reset()
+void Plater::priv::reset(std::string name)
 {
-    Plater::TakeSnapshot snapshot(q, _L("Reset Project"));
+    Plater::TakeSnapshot snapshot(q, _L(name.empty()? "Reset Project" : name));
 
 	clear_warnings();
 
-    set_project_filename(wxEmptyString);
+    set_project_filename(name.empty() ? wxEmptyString : _L(name));
+    set_saved_project(DynamicPrintConfig{}, Model{});
 
     if (view3D->is_layers_editing_enabled())
         view3D->enable_layers_editing(false);
@@ -4800,10 +4830,60 @@ const PrintBase* Plater::current_print() const {
     return printer_technology() == ptFFF ? (PrintBase*)&p->fff_print : (PrintBase*)&p->sla_print;
 }
 
-void Plater::new_project()
+bool Plater::check_project_unsaved_changes() {
+    if (wxGetApp().app_config->get("default_action_on_new_project") == "1" && p->has_project_change(wxGetApp().preset_bundle->full_config_secure(), p->model))
+    {
+        wxMessageDialog diag = wxMessageDialog(static_cast<wxWindow*>(this), _L("You have unsaved Changed, do you want to save your project or to remove all settings and objects?"), wxString(SLIC3R_APP_NAME), wxYES_NO | wxCANCEL | wxYES_DEFAULT | wxCENTRE);
+        diag.SetYesNoLabels(_L("Discard"), _L("Save"));
+        //diag.SetOKLabel(_L("Always discard"));
+        int result = diag.ShowModal();
+        if (result == wxID_CANCEL)
+            return false;
+        else if (result == wxID_NO)
+            save_project_as_3mf(into_path(get_project_filename(".3mf")));
+        //else if (result == wxID_OK)
+            //wxGetApp().app_config->set("default_action_on_new_project", "0");
+    }
+    return true;
+}
+
+bool Plater::ask_for_new_project(std::string project_name)
 {
+    if (!check_project_unsaved_changes())
+        return false;
+    return new_project(project_name);
+}
+
+bool Plater::new_project(std::string project_name)
+{
+    //ask to know what to do with unsaved conf change: 
+    // if discard or save, we can make sur it's reset
+    // if cancel, then do not touch them
+    if (wxGetApp().app_config->get("default_action_preset_on_new_project") == "0" && wxGetApp().check_unsaved_changes()) {
+
+        //if (!config.empty()) {
+        //    Preset::normalize(config);
+        //    wxGetApp().preset_bundle->
+        //    wxGetApp().preset_bundle->load_config_model(filename.string(), std::move(config));
+        //    if (printer_technology == ptFFF)
+        //        CustomGCode::update_custom_gcode_per_print_z_from_config(model.custom_gcode_per_print_z, &wxGetApp().preset_bundle->project_config);
+        //    // For exporting from the amf/3mf we shouldn't check printer_presets for the containing information about "Print Host upload"
+        //    wxGetApp().load_current_presets(false);
+        //    is_project_file = true;
+        //}
+        PrinterTechnology printer_technology = wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology();
+        for (Tab* tab : wxGetApp().tabs_list)
+            if (tab->supports_printer_technology(printer_technology) && tab->current_preset_is_dirty()) {
+                std::vector<std::string> dirty_options = tab->get_presets()->current_dirty_options();
+                for (std::string key : dirty_options) {
+                    tab->get_presets()->get_edited_preset().config.set_key_value(key, tab->get_presets()->get_selected_preset().config.option(key)->clone());
+                }
+                tab->update_dirty();
+            }
+    }
     p->select_view_3D("3D");
-    wxPostEvent(p->view3D->get_wxglcanvas(), SimpleEvent(EVT_GLTOOLBAR_DELETE_ALL));
+    p->reset(project_name);
+    return true;
 }
 
 void Plater::load_project()
@@ -4829,6 +4909,7 @@ void Plater::load_project(const wxString& filename)
     input_paths.push_back(into_path(filename));
 
     std::vector<size_t> res = load_files(input_paths);
+    p->set_saved_project(wxGetApp().preset_bundle->full_config_secure(), p->model);
 
     // if res is empty no data has been loaded
     if (!res.empty())
@@ -5156,11 +5237,15 @@ void Plater::select_all() { p->select_all(); }
 void Plater::deselect_all() { p->deselect_all(); }
 
 void Plater::remove(size_t obj_idx) { p->remove(obj_idx); }
-void Plater::reset() { p->reset(); }
 void Plater::reset_with_confirm()
 {
-    if (wxMessageDialog(static_cast<wxWindow*>(this), _L("All objects will be removed, continue?"), wxString(SLIC3R_APP_NAME) + " - " + _L("Delete all"), wxYES_NO | wxCANCEL | wxYES_DEFAULT | wxCENTRE).ShowModal() == wxID_YES)
-        reset();
+    wxMessageDialog dialog(static_cast<wxWindow*>(this), _L("All objects will be removed, continue?"), wxString(SLIC3R_APP_NAME) + " - " + _L("Delete all"), wxYES_NO | wxCANCEL | wxYES_DEFAULT | wxCENTRE);
+    dialog.SetYesNoLabels("New Project", "Erase all objects");
+    int result = dialog.ShowModal();
+    if (result == wxID_YES)
+        ask_for_new_project();
+    else if (result == wxID_NO)
+        p->remove_all();
 }
 
 void Plater::delete_object_from_model(size_t obj_idx) { p->delete_object_from_model(obj_idx); }
@@ -5539,12 +5624,11 @@ void Plater::export_amf()
     }
 }
 
-void Plater::export_3mf(const boost::filesystem::path& output_path)
+void Plater::save_project_as_3mf(const boost::filesystem::path& output_path)
 {
-    if (p->model.objects.empty()) { return; }
+    //if (p->model.objects.empty()) { return; }
 
     wxString path;
-    bool export_config = true;
     if (output_path.empty())
     {
         path = p->get_export_file(FT_3MF);
@@ -5574,10 +5658,11 @@ void Plater::export_3mf(const boost::filesystem::path& output_path)
         !show_support_on_thumbnails, // parts_only
         show_bed_on_thumbnails, // show_bed
         true); // transparent_background
-    if (Slic3r::store_3mf(path_u8.c_str(), &p->model, export_config ? &cfg : nullptr, full_pathnames, &thumbnail_data)) {
+    if (Slic3r::store_3mf(path_u8.c_str(), &p->model, &cfg, full_pathnames, &thumbnail_data)) {
         // Success
         p->statusbar()->set_status_text(format_wxstr(_L("3MF file exported to %s"), path));
-        p->set_project_filename(path);
+        p->set_project_filename(path); 
+        p->set_saved_project(cfg, p->model);
     }
     else {
         // Failure
diff --git a/src/slic3r/GUI/Plater.hpp b/src/slic3r/GUI/Plater.hpp
index ed428b8c3..1b5e80740 100644
--- a/src/slic3r/GUI/Plater.hpp
+++ b/src/slic3r/GUI/Plater.hpp
@@ -139,7 +139,9 @@ public:
     SLAPrint& sla_print();
     const PrintBase* current_print() const;
 
-    void new_project();
+    bool check_project_unsaved_changes();
+    bool ask_for_new_project(std::string project_name = "");
+    bool new_project(std::string project_name = "");
     void load_project();
     void load_project(const wxString& filename);
     void add_model(bool imperial_units = false);
@@ -184,7 +186,6 @@ public:
     void select_all();
     void deselect_all();
     void remove(size_t obj_idx);
-    void reset();
     void reset_with_confirm();
     void delete_object_from_model(size_t obj_idx);
     void remove_selected();
@@ -201,7 +202,7 @@ public:
     void export_gcode(bool prefer_removable);
     void export_stl(bool extended = false, bool selection_only = false);
     void export_amf();
-    void export_3mf(const boost::filesystem::path& output_path = boost::filesystem::path());
+    void save_project_as_3mf(const boost::filesystem::path& output_path = boost::filesystem::path());
     void reload_from_disk();
     void reload_all_from_disk();
     bool has_toolpaths_to_export() const;
diff --git a/src/slic3r/GUI/Preferences.cpp b/src/slic3r/GUI/Preferences.cpp
index 3ee5b91e7..85695978b 100644
--- a/src/slic3r/GUI/Preferences.cpp
+++ b/src/slic3r/GUI/Preferences.cpp
@@ -191,6 +191,20 @@ void PreferencesDialog::build()
 		def.set_default_value(new ConfigOptionBool{ app_config->get("default_action_on_select_preset") == "none" });
 		option = Option(def, "default_action_on_select_preset");
 		m_optgroup_general->append_single_option_line(option);
+
+		def.label = L("Always keep current preset changes on a new project");
+		def.type = coBool;
+		def.tooltip = L("When you create a new project, it will keep the current preset state, and won't open the preset change dialog.");
+		def.set_default_value(new ConfigOptionBool{ app_config->get("default_action_preset_on_new_project") == "1" });
+		option = Option(def, "default_action_preset_on_new_project");
+		m_optgroup_general->append_single_option_line(option);
+
+		def.label = L("Ask for unsaved project changes");
+		def.type = coBool;
+		def.tooltip = L("Always ask if you want to save your project change if you are going to loose some changes. Or it will discard them by deafult.");
+		def.set_default_value(new ConfigOptionBool{ app_config->get("default_action_on_new_project") == "1" });
+		option = Option(def, "default_action_on_new_project");
+		m_optgroup_general->append_single_option_line(option);
 	}
 #if ENABLE_CUSTOMIZABLE_FILES_ASSOCIATION_ON_WIN
 #ifdef _WIN32