Fixed cut gizmo and SLA shift

src/slic3r/GUI/Gizmos/GLGizmoHollow.cpp

@@ -85,6 +85,12 @@ void GLGizmoHollow::on_render()
         return;
     }
 
+    if (m_state == On) {
+        // This gizmo is showing the object elevated. Tell the common
+        // SelectionInfo object to lie about the actual shift.
+        m_c->selection_info()->set_use_shift(true);
+    }
+
     glsafe(::glEnable(GL_BLEND));
     glsafe(::glEnable(GL_DEPTH_TEST));
 
@@ -828,6 +834,7 @@ void GLGizmoHollow::on_set_state()
         // the gizmo was just turned Off
         m_parent.post_event(SimpleEvent(EVT_GLCANVAS_FORCE_UPDATE));
         m_c->instances_hider()->set_hide_full_scene(false);
+        m_c->selection_info()->set_use_shift(false); // see top of on_render for details
     }
 
     m_old_state = m_state;

src/slic3r/GUI/Gizmos/GLGizmoSlaSupports.cpp

@@ -87,6 +87,12 @@ void GLGizmoSlaSupports::data_changed()
 
 void GLGizmoSlaSupports::on_render()
 {
+    if (m_state == On) {
+        // This gizmo is showing the object elevated. Tell the common
+        // SelectionInfo object to lie about the actual shift.
+        m_c->selection_info()->set_use_shift(true);
+    }
+
     if (!m_sphere.model.is_initialized()) {
         indexed_triangle_set its = its_make_sphere(1.0, double(PI) / 12.0);
         m_sphere.model.init_from(its);
@@ -836,8 +842,10 @@ void GLGizmoSlaSupports::on_set_state()
             m_old_mo_id = -1;
         }
 
-        if (m_state == Off)
+        if (m_state == Off) {
             m_c->instances_hider()->set_hide_full_scene(false);
+            m_c->selection_info()->set_use_shift(true); // see top of on_render for details
+        }
     }
     m_old_state = m_state;
 }

src/slic3r/GUI/Gizmos/GLGizmosCommon.hpp

@@ -163,7 +163,8 @@ public:
     ModelVolume* model_volume() const { return m_model_volume; }
     ModelInstance *model_instance() const;
     int get_active_instance() const;
-    float get_sla_shift() const { return m_z_shift; }
+    float get_sla_shift() const { return m_use_shift ? m_z_shift : 0.f; }
+    void set_use_shift(bool use) { m_use_shift = use; }
 
 protected:
     void on_update() override;
@@ -175,6 +176,7 @@ private:
     ModelVolume* m_model_volume = nullptr;
     // int m_active_inst = -1;
     float m_z_shift = 0.f;
+    bool m_use_shift = false;
 };