diff --git a/src/libslic3r/Preset.cpp b/src/libslic3r/Preset.cpp
index f5c8235ed..09cd38468 100644
--- a/src/libslic3r/Preset.cpp
+++ b/src/libslic3r/Preset.cpp
@@ -1097,14 +1097,6 @@ size_t PresetCollection::update_compatible_internal(const PresetWithVendorProfil
     return m_idx_selected;
 }
 
-// Save the preset under a new name. If the name is different from the old one,
-// a new preset is stored into the list of presets.
-// All presets are marked as not modified and the new preset is activated.
-//void PresetCollection::save_current_preset(const std::string &new_name);
-
-// Delete the current preset, activate the first visible preset.
-//void PresetCollection::delete_current_preset();
-
 // Update a dirty flag of the current preset
 // Return true if the dirty flag changed.
 bool PresetCollection::update_dirty()
diff --git a/src/libslic3r/PresetBundle.hpp b/src/libslic3r/PresetBundle.hpp
index c22599e38..e5e49fb47 100644
--- a/src/libslic3r/PresetBundle.hpp
+++ b/src/libslic3r/PresetBundle.hpp
@@ -143,7 +143,7 @@ public:
 
     const std::string&          get_preset_name_by_alias(const Preset::Type& preset_type, const std::string& alias) const;
 
-    // Save current preset of a required type under a new name. If the name is different from the old one,
+    // Save current preset of a provided type under a new name. If the name is different from the old one,
     // Unselected option would be reverted to the beginning values
     void                        save_changes_for_preset(const std::string& new_name, Preset::Type type, const std::vector<std::string>& unselected_options);
 
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index e2aa6fb7b..5953c5660 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -23,6 +23,7 @@
 #include "slic3r/GUI/3DBed.hpp"
 #include "slic3r/GUI/Plater.hpp"
 #include "slic3r/GUI/MainFrame.hpp"
+#include "slic3r/Utils/UndoRedo.hpp"
 
 #include "GUI_App.hpp"
 #include "GUI_ObjectList.hpp"
@@ -6427,7 +6428,7 @@ void GLCanvas3D::_update_selection_from_hover()
 
         // the selection is going to be modified (Add)
         if (!contains_all) {
-            wxGetApp().plater()->take_snapshot(_(L("Selection-Add from rectangle")));
+            wxGetApp().plater()->take_snapshot(_(L("Selection-Add from rectangle")), UndoRedo::SnapshotType::Selection);
             selection_changed = true;
         }
     }
@@ -6442,7 +6443,7 @@ void GLCanvas3D::_update_selection_from_hover()
 
         // the selection is going to be modified (Remove)
         if (contains_any) {
-            wxGetApp().plater()->take_snapshot(_(L("Selection-Remove from rectangle")));
+            wxGetApp().plater()->take_snapshot(_(L("Selection-Remove from rectangle")), UndoRedo::SnapshotType::Selection);
             selection_changed = true;
         }
     }
diff --git a/src/slic3r/GUI/GUI_ObjectList.cpp b/src/slic3r/GUI/GUI_ObjectList.cpp
index 44f04ef5f..b94110427 100644
--- a/src/slic3r/GUI/GUI_ObjectList.cpp
+++ b/src/slic3r/GUI/GUI_ObjectList.cpp
@@ -10,6 +10,7 @@
 #include "BitmapComboBox.hpp"
 #include "GalleryDialog.hpp"
 #include "MainFrame.hpp"
+#include "slic3r/Utils/UndoRedo.hpp"
 
 #include "OptionsGroup.hpp"
 #include "Tab.hpp"
@@ -3469,7 +3470,7 @@ void ObjectList::update_selections_on_canvas()
         volume_idxs = selection.get_missing_volume_idxs_from(volume_idxs);
         if (volume_idxs.size() > 0)
         {
-            Plater::TakeSnapshot snapshot(wxGetApp().plater(), _(L("Selection-Remove from list")));
+            Plater::TakeSnapshot snapshot(wxGetApp().plater(), _(L("Selection-Remove from list")), UndoRedo::SnapshotType::Selection);
             selection.remove_volumes(mode, volume_idxs);
         }
     }
@@ -3481,7 +3482,7 @@ void ObjectList::update_selections_on_canvas()
         // OR there is no single selection
         if (selection.get_mode() == mode || !single_selection) 
             volume_idxs = selection.get_unselected_volume_idxs_from(volume_idxs);
-        Plater::TakeSnapshot snapshot(wxGetApp().plater(), _(L("Selection-Add from list")));
+        Plater::TakeSnapshot snapshot(wxGetApp().plater(), _(L("Selection-Add from list")), UndoRedo::SnapshotType::Selection);
         selection.add_volumes(mode, volume_idxs, single_selection);
     }
 
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp b/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp
index aac4d6ff7..be8fc331d 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp
@@ -8,6 +8,7 @@
 #include "slic3r/GUI/GUI_App.hpp"
 #include "slic3r/GUI/Camera.hpp"
 #include "slic3r/GUI/Plater.hpp"
+#include "slic3r/Utils/UndoRedo.hpp"
 #include "libslic3r/Model.hpp"
 #include "libslic3r/PresetBundle.hpp"
 #include "libslic3r/TriangleMesh.hpp"
@@ -42,14 +43,14 @@ void GLGizmoPainterBase::activate_internal_undo_redo_stack(bool activate)
 
     if (activate && !m_internal_stack_active) {
         if (std::string str = this->get_gizmo_entering_text(); last_snapshot_name != str)
-            Plater::TakeSnapshot(plater, str);
+            Plater::TakeSnapshot(plater, str, UndoRedo::SnapshotType::EnteringGizmo);
         plater->enter_gizmos_stack();
         m_internal_stack_active = true;
     }
     if (!activate && m_internal_stack_active) {
         plater->leave_gizmos_stack();
         if (std::string str = this->get_gizmo_leaving_text(); last_snapshot_name != str)
-            Plater::TakeSnapshot(plater, str);
+            Plater::TakeSnapshot(plater, str, UndoRedo::SnapshotType::LeavingGizmoWithAction);
         m_internal_stack_active = false;
     }
 }
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoSlaSupports.cpp b/src/slic3r/GUI/Gizmos/GLGizmoSlaSupports.cpp
index a50c503b9..b7a6d89fa 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoSlaSupports.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoSlaSupports.cpp
@@ -4,6 +4,7 @@
 #include "slic3r/GUI/Camera.hpp"
 #include "slic3r/GUI/Gizmos/GLGizmosCommon.hpp"
 #include "slic3r/GUI/MainFrame.hpp"
+#include "slic3r/Utils/UndoRedo.hpp"
 
 #include <GL/glew.h>
 
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index 6404dbb6d..6cef0933a 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -1530,25 +1530,25 @@ struct Plater::priv
         
         void arrange()
         {
-            m->take_snapshot(_(L("Arrange")));
+            m->take_snapshot(_L("Arrange"));
             start(m_arrange_id);
         }
 
         void fill_bed()
         {
-            m->take_snapshot(_(L("Fill bed")));
+            m->take_snapshot(_L("Fill bed"));
             start(m_fill_bed_id);
         }
         
         void optimize_rotation()
         {
-            m->take_snapshot(_(L("Optimize Rotation")));
+            m->take_snapshot(_L("Optimize Rotation"));
             start(m_rotoptimize_id);
         }
         
         void import_sla_arch()
         {
-            m->take_snapshot(_(L("Import SLA archive")));
+            m->take_snapshot(_L("Import SLA archive"));
             start(m_sla_import_id);
         }
         
@@ -1677,8 +1677,9 @@ struct Plater::priv
     void enter_gizmos_stack();
     void leave_gizmos_stack();
 
-    void take_snapshot(const std::string& snapshot_name);
-    void take_snapshot(const wxString& snapshot_name) { this->take_snapshot(std::string(snapshot_name.ToUTF8().data())); }
+    void take_snapshot(const std::string& snapshot_name, UndoRedo::SnapshotType snapshot_type = UndoRedo::SnapshotType::Action);
+    void take_snapshot(const wxString& snapshot_name, UndoRedo::SnapshotType snapshot_type = UndoRedo::SnapshotType::Action)
+        { this->take_snapshot(std::string(snapshot_name.ToUTF8().data()), snapshot_type); }
     int  get_active_snapshot_index();
 
     void undo();
@@ -2062,7 +2063,7 @@ Plater::priv::priv(Plater *q, MainFrame *main_frame)
     }
 
     // Initialize the Undo / Redo stack with a first snapshot.
-    this->take_snapshot(_L("New Project"));
+    this->take_snapshot(_L("New Project"), UndoRedo::SnapshotType::ProjectSeparator);
 
     this->q->Bind(EVT_LOAD_MODEL_OTHER_INSTANCE, [this](LoadFromOtherInstanceEvent& evt) {
         BOOST_LOG_TRIVIAL(trace) << "Received load from other instance event.";
@@ -2818,7 +2819,7 @@ void Plater::priv::delete_all_objects_from_model()
 
 void Plater::priv::reset()
 {
-    Plater::TakeSnapshot snapshot(q, _L("Reset Project"));
+    Plater::TakeSnapshot snapshot(q, _L("Reset Project"), UndoRedo::SnapshotType::ProjectSeparator);
 
 	clear_warnings();
 
@@ -4660,12 +4661,13 @@ int Plater::priv::get_active_snapshot_index()
     return it - ss_stack.begin();
 }
 
-void Plater::priv::take_snapshot(const std::string& snapshot_name)
+void Plater::priv::take_snapshot(const std::string& snapshot_name, const UndoRedo::SnapshotType snapshot_type)
 {
     if (m_prevent_snapshots > 0)
         return;
     assert(m_prevent_snapshots >= 0);
     UndoRedo::SnapshotData snapshot_data;
+    snapshot_data.snapshot_type      = snapshot_type;
     snapshot_data.printer_technology = this->printer_technology;
     if (this->view3D->is_layers_editing_enabled())
         snapshot_data.flags |= UndoRedo::SnapshotData::VARIABLE_LAYER_EDITING_ACTIVE;
@@ -4951,7 +4953,7 @@ void Plater::new_project()
     }
 
     p->select_view_3D("3D");
-    take_snapshot(_L("New Project"));
+    take_snapshot(_L("New Project"), UndoRedo::SnapshotType::ProjectSeparator);
     Plater::SuppressSnapshots suppress(this);
     reset();
     reset_project_dirty_initial_presets();
@@ -4976,7 +4978,7 @@ void Plater::load_project(const wxString& filename)
         return;
 
     // Take the Undo / Redo snapshot.
-    Plater::TakeSnapshot snapshot(this, _L("Load Project") + ": " + wxString::FromUTF8(into_path(filename).stem().string().c_str()));
+    Plater::TakeSnapshot snapshot(this, _L("Load Project") + ": " + wxString::FromUTF8(into_path(filename).stem().string().c_str()), UndoRedo::SnapshotType::ProjectSeparator);
 
     p->reset();
 
@@ -5992,6 +5994,8 @@ void Plater::eject_drive()
 
 void Plater::take_snapshot(const std::string &snapshot_name) { p->take_snapshot(snapshot_name); }
 void Plater::take_snapshot(const wxString &snapshot_name) { p->take_snapshot(snapshot_name); }
+void Plater::take_snapshot(const std::string &snapshot_name, UndoRedo::SnapshotType snapshot_type) { p->take_snapshot(snapshot_name, snapshot_type); }
+void Plater::take_snapshot(const wxString &snapshot_name, UndoRedo::SnapshotType snapshot_type) { p->take_snapshot(snapshot_name, snapshot_type); }
 void Plater::suppress_snapshots() { p->suppress_snapshots(); }
 void Plater::allow_snapshots() { p->allow_snapshots(); }
 void Plater::undo() { p->undo(); }
diff --git a/src/slic3r/GUI/Plater.hpp b/src/slic3r/GUI/Plater.hpp
index c03681a34..8a8255514 100644
--- a/src/slic3r/GUI/Plater.hpp
+++ b/src/slic3r/GUI/Plater.hpp
@@ -37,6 +37,7 @@ using ModelInstancePtrs = std::vector<ModelInstance*>;
 
 namespace UndoRedo {
     class Stack;
+    enum class SnapshotType : unsigned char;
     struct Snapshot;
 }
 
@@ -240,6 +241,9 @@ public:
 
     void take_snapshot(const std::string &snapshot_name);
     void take_snapshot(const wxString &snapshot_name);
+    void take_snapshot(const std::string &snapshot_name, UndoRedo::SnapshotType snapshot_type);
+    void take_snapshot(const wxString &snapshot_name, UndoRedo::SnapshotType snapshot_type);
+
     void undo();
     void redo();
     void undo_to(int selection);
@@ -391,6 +395,12 @@ public:
 			m_plater->take_snapshot(snapshot_name);
 			m_plater->suppress_snapshots();
 		}
+        TakeSnapshot(Plater *plater, const wxString &snapshot_name, UndoRedo::SnapshotType snapshot_type) : m_plater(plater)
+        {
+            m_plater->take_snapshot(snapshot_name, snapshot_type);
+            m_plater->suppress_snapshots();
+        }
+
 		~TakeSnapshot()
 		{
 			m_plater->allow_snapshots();
diff --git a/src/slic3r/GUI/Selection.cpp b/src/slic3r/GUI/Selection.cpp
index 4a9c7cd56..3ab9b7bdc 100644
--- a/src/slic3r/GUI/Selection.cpp
+++ b/src/slic3r/GUI/Selection.cpp
@@ -10,6 +10,7 @@
 #include "Gizmos/GLGizmoBase.hpp"
 #include "Camera.hpp"
 #include "Plater.hpp"
+#include "slic3r/Utils/UndoRedo.hpp"
 
 #include "libslic3r/LocalesUtils.hpp"
 #include "libslic3r/Model.hpp"
@@ -162,7 +163,7 @@ void Selection::add(unsigned int volume_idx, bool as_single_selection, bool chec
     needs_reset |= is_any_modifier() && !volume->is_modifier;
 
     if (!already_contained || needs_reset) {
-        wxGetApp().plater()->take_snapshot(_L("Selection-Add"));
+        wxGetApp().plater()->take_snapshot(_L("Selection-Add"), UndoRedo::SnapshotType::Selection);
 
         if (needs_reset)
             clear();
@@ -203,7 +204,7 @@ void Selection::remove(unsigned int volume_idx)
     if (!contains_volume(volume_idx))
         return;
 
-    wxGetApp().plater()->take_snapshot(_L("Selection-Remove"));
+    wxGetApp().plater()->take_snapshot(_L("Selection-Remove"), UndoRedo::SnapshotType::Selection);
 
     GLVolume* volume = (*m_volumes)[volume_idx];
 
@@ -235,7 +236,7 @@ void Selection::add_object(unsigned int object_idx, bool as_single_selection)
         (as_single_selection && matches(volume_idxs)))
         return;
 
-    wxGetApp().plater()->take_snapshot(_L("Selection-Add Object"));
+    wxGetApp().plater()->take_snapshot(_L("Selection-Add Object"), UndoRedo::SnapshotType::Selection);
 
     // resets the current list if needed
     if (as_single_selection)
@@ -254,7 +255,7 @@ void Selection::remove_object(unsigned int object_idx)
     if (!m_valid)
         return;
 
-    wxGetApp().plater()->take_snapshot(_L("Selection-Remove Object"));
+    wxGetApp().plater()->take_snapshot(_L("Selection-Remove Object"), UndoRedo::SnapshotType::Selection);
 
     do_remove_object(object_idx);
 
@@ -272,7 +273,7 @@ void Selection::add_instance(unsigned int object_idx, unsigned int instance_idx,
         (as_single_selection && matches(volume_idxs)))
         return;
 
-    wxGetApp().plater()->take_snapshot(_L("Selection-Add Instance"));
+    wxGetApp().plater()->take_snapshot(_L("Selection-Add Instance"), UndoRedo::SnapshotType::Selection);
 
     // resets the current list if needed
     if (as_single_selection)
@@ -291,7 +292,7 @@ void Selection::remove_instance(unsigned int object_idx, unsigned int instance_i
     if (!m_valid)
         return;
 
-    wxGetApp().plater()->take_snapshot(_L("Selection-Remove Instance"));
+    wxGetApp().plater()->take_snapshot(_L("Selection-Remove Instance"), UndoRedo::SnapshotType::Selection);
 
     do_remove_instance(object_idx, instance_idx);
 
@@ -388,7 +389,7 @@ void Selection::add_all()
     if ((unsigned int)m_list.size() == count)
         return;
     
-    wxGetApp().plater()->take_snapshot(_(L("Selection-Add All")));
+    wxGetApp().plater()->take_snapshot(_(L("Selection-Add All")), UndoRedo::SnapshotType::Selection);
 
     m_mode = Instance;
     clear();
@@ -413,7 +414,7 @@ void Selection::remove_all()
 // Not taking the snapshot with non-empty Redo stack will likely be more confusing than losing the Redo stack.
 // Let's wait for user feedback.
 //    if (!wxGetApp().plater()->can_redo())
-        wxGetApp().plater()->take_snapshot(_L("Selection-Remove All"));
+        wxGetApp().plater()->take_snapshot(_L("Selection-Remove All"), UndoRedo::SnapshotType::Selection);
 
     m_mode = Instance;
     clear();
diff --git a/src/slic3r/Utils/UndoRedo.cpp b/src/slic3r/Utils/UndoRedo.cpp
index a19788ab9..f5d418fa7 100644
--- a/src/slic3r/Utils/UndoRedo.cpp
+++ b/src/slic3r/Utils/UndoRedo.cpp
@@ -556,6 +556,12 @@ public:
 
 	// Snapshot history (names with timestamps).
 	const std::vector<Snapshot>& 	snapshots() const { return m_snapshots; }
+	const Snapshot&				    snapshot(size_t time) const {
+		const auto it = std::lower_bound(m_snapshots.cbegin(), m_snapshots.cend(), UndoRedo::Snapshot(time));
+		assert(it != m_snapshots.end() && it->timestamp == time);
+		return *it;
+	}
+
 	// Timestamp of the active snapshot.
 	size_t 							active_snapshot_time() const { return m_active_snapshot_time; }
 	bool 							temp_snapshot_active() const { return m_snapshots.back().timestamp == m_active_snapshot_time && ! m_snapshots.back().is_topmost_captured(); }
@@ -1097,6 +1103,7 @@ bool Stack::redo(Slic3r::Model& model, Slic3r::GUI::GLGizmosManager& gizmos, siz
 const Selection& Stack::selection_deserialized() const { return pimpl->selection_deserialized(); }
 
 const std::vector<Snapshot>& Stack::snapshots() const { return pimpl->snapshots(); }
+const Snapshot& Stack::snapshot(size_t time) const { return pimpl->snapshot(time); }
 size_t Stack::active_snapshot_time() const { return pimpl->active_snapshot_time(); }
 bool Stack::temp_snapshot_active() const { return pimpl->temp_snapshot_active(); }
 
diff --git a/src/slic3r/Utils/UndoRedo.hpp b/src/slic3r/Utils/UndoRedo.hpp
index e120c4f79..d29c0e979 100644
--- a/src/slic3r/Utils/UndoRedo.hpp
+++ b/src/slic3r/Utils/UndoRedo.hpp
@@ -24,6 +24,23 @@ namespace GUI {
 
 namespace UndoRedo {
 
+enum class SnapshotType : unsigned char {
+	// Some action modifying project state.
+	Action,
+	// Selection change at the Plater.
+	Selection,
+	// New project, Reset project, Load project ...
+	ProjectSeparator,
+	// Entering a Gizmo, which opens a secondary Undo / Redo stack.
+	EnteringGizmo,
+	// Leaving a Gizmo, which closes a secondary Undo / Redo stack. 
+	// No action modifying a project state was done between EnteringGizmo / LeavingGizmo.
+	LeavingGizmoNoAction,
+	// Leaving a Gizmo, which closes a secondary Undo / Redo stack.
+	// Some action modifying a project state was done between EnteringGizmo / LeavingGizmo.
+	LeavingGizmoWithAction,
+};
+
 // Data structure to be stored with each snapshot.
 // Storing short data (bit masks, ints) with each snapshot instead of being serialized into the Undo / Redo stack
 // is likely cheaper in term of both the runtime and memory allocation.
@@ -34,6 +51,7 @@ struct SnapshotData
 	// Constructor is defined in .cpp due to the forward declaration of enum PrinterTechnology.
 	SnapshotData();
 
+	SnapshotType        snapshot_type;
 	PrinterTechnology 	printer_technology;
 	// Bitmap of Flags (see the Flags enum).
 	unsigned int        flags;
@@ -122,10 +140,13 @@ public:
 	// There is one additional snapshot taken at the very end, which indicates the current unnamed state.
 
 	const std::vector<Snapshot>& snapshots() const;
+	const Snapshot& 		     snapshot(size_t time) const;
+
 	// Timestamp of the active snapshot. One of the snapshots of this->snapshots() shall have Snapshot::timestamp equal to this->active_snapshot_time().
-	// The snapshot time indicates start of an operation, which is finished at the time of the following snapshot, therefore
-	// the active snapshot is the successive snapshot. The same logic applies to the time_to_load parameter of undo() and redo() operations.
+	// The active snapshot may be a special placeholder "@@@ Topmost @@@" indicating an uncaptured current state,
+	// or the active snapshot may be an active state to which the application state was undoed or redoed.
 	size_t active_snapshot_time() const;
+	const Snapshot& active_snapshot() const { return this->snapshot(this->active_snapshot_time()); }
 	// Temporary snapshot is active if the topmost snapshot is active and it has not been captured yet.
 	// In that case the Undo action will capture the last snapshot.
 	bool   temp_snapshot_active() const;