Another approach to fix undo redo:

Do not open gizmo on shortcut key: only create volume

src/slic3r/GUI/Gizmos/GLGizmoBase.hpp

@@ -174,7 +174,7 @@ public:
     /// <summary>
     /// Is called when data (Selection) is changed
     /// </summary>
-    virtual void data_changed(bool is_serializing){};
+    virtual void data_changed(){};
 
     /// <summary>
     /// Implement when want to process mouse events in gizmo

src/slic3r/GUI/Gizmos/GLGizmoCut.cpp

@@ -2510,7 +2510,7 @@ CommonGizmosDataID GLGizmoCut3D::on_get_requirements() const {
               | int(CommonGizmosDataID::ObjectClipper));
 }
 
-void GLGizmoCut3D::data_changed(bool is_serializing)
+void GLGizmoCut3D::data_changed()
 {
     update_bb();
     if (auto oc = m_c->object_clipper())

src/slic3r/GUI/Gizmos/GLGizmoCut.hpp

@@ -256,7 +256,7 @@ protected:
     std::string get_gizmo_leaving_text() const override     { return _u8L("Leaving Cut gizmo"); }
     std::string get_action_snapshot_name() const override   { return _u8L("Cut gizmo editing"); }
 
-    void data_changed(bool is_serializing) override;
+    void data_changed() override;
 
 private:
     void set_center(const Vec3d& center, bool update_tbb = false);

src/slic3r/GUI/Gizmos/GLGizmoEmboss.cpp

@@ -312,6 +312,21 @@ void GLGizmoEmboss::create_volume(ModelVolumeType volume_type)
     }
 }
 
+void GLGizmoEmboss::on_shortcut_key() {
+    set_volume_by_selection();
+    if (m_volume == nullptr) {
+        // No volume to select from selection so create volume.
+        // NOTE: After finish job for creation emboss Text volume,
+        // GLGizmoEmboss will be opened
+        create_volume(ModelVolumeType::MODEL_PART);
+    } else {
+        // shortcut is pressed when text is selected soo start edit it.
+        auto &mng = m_parent.get_gizmos_manager();
+        if (mng.get_current_type() != GLGizmosManager::Emboss)
+            mng.open_gizmo(GLGizmosManager::Emboss);
+    }
+}
+
 bool GLGizmoEmboss::init_create(ModelVolumeType volume_type)
 {
     // check valid volume type
@@ -628,7 +643,6 @@ static void draw_mouse_offset(const std::optional<Vec2d> &offset)
 
 void GLGizmoEmboss::on_render_input_window(float x, float y, float bottom_limit)
 {
-    m_is_just_opened = false;
     assert(m_volume != nullptr);
     // Do not render window for not selected text volume
     if (m_volume == nullptr ||
@@ -767,16 +781,7 @@ void GLGizmoEmboss::on_set_state()
 
         // Immediately after set state On is called function data_changed(), 
         // where one could distiguish undo/redo serialization from opening by letter 'T'
-        set_volume_by_selection();
-
-        // when open window by "T" and no valid volume is selected, so Create new one
-        if (m_volume == nullptr) {
-            // reopen gizmo when new object is created
-            m_state = GLGizmoBase::Off;
-            // start creating new object
-            return;
-        }
-        m_is_just_opened = true;
+        // set_volume_by_selection();
 
         // change position of just opened emboss window
         if (m_allow_open_near_volume) {
@@ -794,9 +799,7 @@ void GLGizmoEmboss::on_set_state()
     }
 }
 
-void GLGizmoEmboss::data_changed(bool is_serializing) {
-    if (is_serializing)
-        reset_volume();
+void GLGizmoEmboss::data_changed() {
     set_volume_by_selection();
 }
 
@@ -1001,13 +1004,15 @@ void GLGizmoEmboss::set_volume_by_selection()
     if (gl_volume == nullptr)
         return reset_volume();
 
-    const ModelObjectPtrs &objects = selection.get_model()->objects;
-    ModelVolume *volume =get_model_volume(*gl_volume, objects);
+    const ModelObjectPtrs &objects = m_parent.get_model()->objects;
+    ModelVolume *volume = get_model_volume(*gl_volume, objects);
     if (volume == nullptr)
         return reset_volume();
 
     // is same volume as actual selected?
-    if (volume->id() == m_volume_id)
+    if (volume->id() == m_volume_id && 
+        m_volume != nullptr && 
+        volume->text_configuration->style == m_volume->text_configuration->style)
         return;
 
     // for changed volume notification is NOT valid

src/slic3r/GUI/Gizmos/GLGizmoEmboss.hpp

@@ -47,6 +47,10 @@ public:
     /// <param name="volume_type">Object part / Negative volume / Modifier</param>
     void create_volume(ModelVolumeType volume_type);
 
+    /// <summary>
+    /// Handle pressing of shortcut
+    /// </summary>
+    void on_shortcut_key();
 protected:
     bool on_init() override;
     bool on_is_activable() const override;
@@ -57,7 +61,7 @@ protected:
     void on_render_input_window(float x, float y, float bottom_limit) override;
     bool on_is_selectable() const override { return false; }
     void on_set_state() override;    
-    void data_changed(bool is_serializing) override; // selection changed
+    void data_changed() override; // selection changed
     void on_set_hover_id() override{ m_rotate_gizmo.set_hover_id(m_hover_id); }
     void on_enable_grabber(unsigned int id) override { m_rotate_gizmo.enable_grabber(); }
     void on_disable_grabber(unsigned int id) override { m_rotate_gizmo.disable_grabber(); }
@@ -304,10 +308,6 @@ private:
     // True when m_text contain character unknown by selected font
     bool m_text_contain_unknown_glyph = false;
 
-    // True from on_set_state(State::On) to first call of on_render_input_window()
-    // To know that on data_change when no volume is selected create new one
-    bool m_is_just_opened = false;
-
     // cancel for previous update of volume to cancel finalize part
     std::shared_ptr<std::atomic<bool>> m_job_cancel;
 

src/slic3r/GUI/Gizmos/GLGizmoFdmSupports.cpp

@@ -387,9 +387,9 @@ void GLGizmoFdmSupports::select_facets_by_angle(float threshold_deg, bool block)
     m_parent.set_as_dirty();
 }
 
-void GLGizmoFdmSupports::data_changed(bool is_serializing)
+void GLGizmoFdmSupports::data_changed()
 {
-    GLGizmoPainterBase::data_changed(is_serializing);
+    GLGizmoPainterBase::data_changed();
     if (! m_c->selection_info())
         return;
 

src/slic3r/GUI/Gizmos/GLGizmoFdmSupports.hpp

@@ -28,7 +28,7 @@ protected:
 
 private:
     bool on_init() override;
-    void data_changed(bool is_serializing) override;
+    void data_changed() override;
 
     void update_model_object() const override;
     void update_from_model_object() override;

src/slic3r/GUI/Gizmos/GLGizmoFlatten.cpp

@@ -56,7 +56,7 @@ bool GLGizmoFlatten::on_mouse(const wxMouseEvent &mouse_event)
     return false;
 }
 
-void GLGizmoFlatten::data_changed(bool is_serializing)
+void GLGizmoFlatten::data_changed()
 {
     const Selection &  selection    = m_parent.get_selection();
     const ModelObject *model_object = nullptr;

src/slic3r/GUI/Gizmos/GLGizmoFlatten.hpp

@@ -55,7 +55,7 @@ public:
     /// <returns>Return True when use the information otherwise False.</returns>
     bool on_mouse(const wxMouseEvent &mouse_event) override;
 
-    void data_changed(bool is_serializing) override;
+    void data_changed() override;
 protected:
     bool on_init() override;
     std::string on_get_name() const override;

src/slic3r/GUI/Gizmos/GLGizmoHollow.cpp

@@ -42,7 +42,7 @@ bool GLGizmoHollow::on_init()
     return true;
 }
 
-void GLGizmoHollow::data_changed(bool is_serializing)
+void GLGizmoHollow::data_changed()
 {
     if (! m_c->selection_info())
         return;

src/slic3r/GUI/Gizmos/GLGizmoHollow.hpp

@@ -24,7 +24,7 @@ class GLGizmoHollow : public GLGizmoSlaBase
 {
 public:
     GLGizmoHollow(GLCanvas3D& parent, const std::string& icon_filename, unsigned int sprite_id);
-    void data_changed(bool is_serializing) override;
+    void data_changed() override;
     bool gizmo_event(SLAGizmoEventType action, const Vec2d& mouse_position, bool shift_down, bool alt_down, bool control_down);
     void delete_selected_points();    
     bool is_selection_rectangle_dragging() const override {

src/slic3r/GUI/Gizmos/GLGizmoMeasure.cpp

@@ -454,7 +454,7 @@ bool GLGizmoMeasure::on_mouse(const wxMouseEvent &mouse_event)
     return false;
 }
 
-void GLGizmoMeasure::data_changed(bool is_serializing)
+void GLGizmoMeasure::data_changed()
 {
     m_parent.toggle_sla_auxiliaries_visibility(false, nullptr, -1);
 

src/slic3r/GUI/Gizmos/GLGizmoMeasure.hpp

@@ -156,7 +156,7 @@ public:
     /// <returns>Return True when use the information otherwise False.</returns>
     bool on_mouse(const wxMouseEvent &mouse_event) override;
 
-    void data_changed(bool is_serializing) override;
+    void data_changed() override;
 
     bool gizmo_event(SLAGizmoEventType action, const Vec2d& mouse_position, bool shift_down, bool alt_down, bool control_down);
 

src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp

@@ -147,9 +147,9 @@ void GLGizmoMmuSegmentation::render_painter_gizmo()
     glsafe(::glDisable(GL_BLEND));
 }
 
-void GLGizmoMmuSegmentation::data_changed(bool is_serializing)
+void GLGizmoMmuSegmentation::data_changed()
 {
-    GLGizmoPainterBase::data_changed(is_serializing);
+    GLGizmoPainterBase::data_changed();
     if (m_state != On || wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology() != ptFFF || wxGetApp().extruders_edited_cnt() <= 1)
         return;
 

src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.hpp

@@ -90,7 +90,7 @@ public:
 
     void render_painter_gizmo() override;
 
-    void data_changed(bool is_serializing) override;
+    void data_changed() override;
 
     void render_triangles(const Selection& selection) const override;
 

src/slic3r/GUI/Gizmos/GLGizmoMove.cpp

@@ -51,7 +51,7 @@ bool GLGizmoMove3D::on_mouse(const wxMouseEvent &mouse_event) {
     return use_grabbers(mouse_event);
 }
 
-void GLGizmoMove3D::data_changed(bool is_serializing) {
+void GLGizmoMove3D::data_changed() {
     m_grabbers[2].enabled = !m_parent.get_selection().is_wipe_tower();
 }
 

src/slic3r/GUI/Gizmos/GLGizmoMove.hpp

@@ -51,7 +51,7 @@ public:
     /// <summary>
     /// Detect reduction of move for wipetover on selection change
     /// </summary>
-    void data_changed(bool is_serializing) override;
+    void data_changed() override;
 protected:
     bool on_init() override;
     std::string on_get_name() const override;

src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp

@@ -31,7 +31,7 @@ GLGizmoPainterBase::~GLGizmoPainterBase()
         s_sphere.reset();
 }
 
-void GLGizmoPainterBase::data_changed(bool is_serializing)
+void GLGizmoPainterBase::data_changed()
 {
     if (m_state != On)
         return;

src/slic3r/GUI/Gizmos/GLGizmoPainterBase.hpp

@@ -83,7 +83,7 @@ private:
 public:
     GLGizmoPainterBase(GLCanvas3D& parent, const std::string& icon_filename, unsigned int sprite_id);
     ~GLGizmoPainterBase() override;
-    void data_changed(bool is_serializing) override;
+    void data_changed() override;
     virtual bool gizmo_event(SLAGizmoEventType action, const Vec2d& mouse_position, bool shift_down, bool alt_down, bool control_down);
 
     // Following function renders the triangles and cursor. Having this separated

src/slic3r/GUI/Gizmos/GLGizmoRotate.cpp

@@ -600,7 +600,7 @@ bool GLGizmoRotate3D::on_mouse(const wxMouseEvent &mouse_event)
     return use_grabbers(mouse_event);
 }
 
-void GLGizmoRotate3D::data_changed(bool is_serializing) {
+void GLGizmoRotate3D::data_changed() {
     if (m_parent.get_selection().is_wipe_tower()) {
 #if !ENABLE_WORLD_COORDINATE
         const DynamicPrintConfig& config = wxGetApp().preset_bundle->prints.get_edited_preset().config;

src/slic3r/GUI/Gizmos/GLGizmoRotate.hpp

@@ -146,7 +146,7 @@ public:
     /// <returns>Return True when use the information otherwise False.</returns>
     bool on_mouse(const wxMouseEvent &mouse_event) override;
 
-    void data_changed(bool is_serializing) override;
+    void data_changed() override;
 protected:
     bool on_init() override;
     std::string on_get_name() const override;

src/slic3r/GUI/Gizmos/GLGizmoScale.cpp

@@ -105,7 +105,7 @@ void GLGizmoScale3D::enable_ununiversal_scale(bool enable)
         m_grabbers[i].enabled = enable;
 }
 
-void GLGizmoScale3D::data_changed(bool is_serializing)
+void GLGizmoScale3D::data_changed()
 {
 #if ENABLE_WORLD_COORDINATE
     set_scale(Vec3d::Ones());

src/slic3r/GUI/Gizmos/GLGizmoScale.hpp

@@ -82,7 +82,7 @@ public:
     /// <returns>Return True when use the information otherwise False.</returns>
     bool on_mouse(const wxMouseEvent &mouse_event) override;
 
-    void data_changed(bool is_serializing) override;
+    void data_changed() override;
     void enable_ununiversal_scale(bool enable);
 protected:
     virtual bool on_init() override;

src/slic3r/GUI/Gizmos/GLGizmoSlaSupports.cpp

@@ -49,7 +49,7 @@ bool GLGizmoSlaSupports::on_init()
     return true;
 }
 
-void GLGizmoSlaSupports::data_changed(bool is_serializing)
+void GLGizmoSlaSupports::data_changed()
 {
     if (! m_c->selection_info())
         return;

src/slic3r/GUI/Gizmos/GLGizmoSlaSupports.hpp

@@ -55,7 +55,7 @@ private:
 public:
     GLGizmoSlaSupports(GLCanvas3D& parent, const std::string& icon_filename, unsigned int sprite_id);
     virtual ~GLGizmoSlaSupports() = default;
-    void data_changed(bool is_serializing) override;
+    void data_changed() override;
     bool gizmo_event(SLAGizmoEventType action, const Vec2d& mouse_position, bool shift_down, bool alt_down, bool control_down);
     void delete_selected_points(bool force = false);
     //ClippingPlane get_sla_clipping_plane() const;

src/slic3r/GUI/Gizmos/GLGizmosManager.cpp

@@ -223,7 +223,7 @@ void GLGizmosManager::update_data()
         m_common_gizmos_data->update(get_current()
                                    ? get_current()->get_requirements()
                                    : CommonGizmosDataID(0));
-    if (m_current != Undefined) m_gizmos[m_current]->data_changed(m_serializing);
+    if (m_current != Undefined) m_gizmos[m_current]->data_changed();
 }
 
 bool GLGizmosManager::is_running() const
@@ -245,7 +245,7 @@ bool GLGizmosManager::handle_shortcut(int key)
     // allowe open shortcut even when selection is empty    
     if (GLGizmoBase* gizmo_emboss = m_gizmos[Emboss].get();
         is_key(gizmo_emboss->get_shortcut_key())) {
-        dynamic_cast<GLGizmoEmboss *>(gizmo_emboss)->create_volume(ModelVolumeType::MODEL_PART);
+        dynamic_cast<GLGizmoEmboss *>(gizmo_emboss)->on_shortcut_key();
         return true;
     }