diff --git a/src/slic3r/GUI/Gizmos/GLGizmoFlatten.cpp b/src/slic3r/GUI/Gizmos/GLGizmoFlatten.cpp
index 264e1d629e..5475e75520 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoFlatten.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoFlatten.cpp
@@ -143,7 +143,9 @@ void GLGizmoFlatten::set_flattening_data(const ModelObject* model_object, int in
 {
     if (model_object != m_old_model_object || instance_id != m_old_instance_id) {
         m_planes.clear();
-        on_unregister_raycasters_for_picking();
+        if (get_state() == On) { // Only touch the raycasters if it's current
+            on_unregister_raycasters_for_picking();
+        }
     }
 }