diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 68e12d35b..2701fcea5 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -1378,11 +1378,24 @@ bool GLCanvas3D::Selection::is_single_full_instance() const
     if (m_type == SingleFullInstance)
         return true;
 
-    int object_idx = m_valid ? get_object_idx() : -1;
-    if ((0 <= object_idx) && (object_idx < (int)m_model->objects.size()))
-        return m_model->objects[object_idx]->volumes.size() == m_list.size();
+    if (m_list.empty() || m_volumes->empty())
+        return false;
 
-    return false;
+    int object_idx = m_valid ? get_object_idx() : -1;
+    if (object_idx == -1)
+        return false;
+
+    int instance_idx = (*m_volumes)[*m_list.begin()]->instance_idx();
+
+    std::set<int> volumes_idxs;
+    for (const GLVolume* v : *m_volumes)
+    {
+        int volume_idx = v->volume_idx();
+        if ((v->object_idx() == object_idx) && (v->instance_idx() == instance_idx) && (volume_idx >= 0))
+            volumes_idxs.insert(volume_idx);
+    }
+
+    return m_model->objects[object_idx]->volumes.size() == volumes_idxs.size();
 }
 
 bool GLCanvas3D::Selection::is_from_single_object() const
diff --git a/src/slic3r/GUI/GLGizmo.cpp b/src/slic3r/GUI/GLGizmo.cpp
index b5f78362b..2f39f7d69 100644
--- a/src/slic3r/GUI/GLGizmo.cpp
+++ b/src/slic3r/GUI/GLGizmo.cpp
@@ -1768,6 +1768,8 @@ void GLGizmoSlaSupports::set_sla_support_data(ModelObject* model_object, const G
     m_starting_center = Vec3d::Zero();
     m_old_model_object = m_model_object;
     m_model_object = model_object;
+    if (selection.is_empty())
+        m_old_instance_id = -1;
 
     if ((model_object != nullptr) && selection.is_from_single_instance())
     {
@@ -2048,8 +2050,10 @@ void GLGizmoSlaSupports::clicked_on_object(const Vec2d& mouse_position)
     int instance_id = m_parent.get_selection().get_instance_idx();
     if (m_old_instance_id != instance_id)
     {
+        bool something_selected = (m_old_instance_id != -1);
         m_old_instance_id = instance_id;
-        return;
+        if (something_selected)
+            return;
     }
     if (instance_id == -1)
         return;