diff --git a/src/libslic3r/Model.cpp b/src/libslic3r/Model.cpp
index d0410c2d4..4ff0a5c1b 100644
--- a/src/libslic3r/Model.cpp
+++ b/src/libslic3r/Model.cpp
@@ -1841,13 +1841,15 @@ indexed_triangle_set FacetsAnnotation::get_facets(const ModelVolume& mv, FacetSu
 
 
 
-void FacetsAnnotation::set(const TriangleSelector& selector)
+bool FacetsAnnotation::set(const TriangleSelector& selector)
 {
     std::map<int, std::vector<bool>> sel_map = selector.serialize();
     if (sel_map != m_data) {
         m_data = sel_map;
         update_timestamp();
+        return true;
     }
+    return false;
 }
 
 
diff --git a/src/libslic3r/Model.hpp b/src/libslic3r/Model.hpp
index 3127af5ba..16f3f00ad 100644
--- a/src/libslic3r/Model.hpp
+++ b/src/libslic3r/Model.hpp
@@ -406,7 +406,7 @@ public:
     using ClockType = std::chrono::steady_clock;
 
     const std::map<int, std::vector<bool>>& get_data() const { return m_data; }
-    void set(const TriangleSelector& selector);
+    bool set(const TriangleSelector& selector);
     indexed_triangle_set get_facets(const ModelVolume& mv, FacetSupportType type) const;
     void clear();
 
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoFdmSupports.cpp b/src/slic3r/GUI/Gizmos/GLGizmoFdmSupports.cpp
index 417d101ea..13c9cfef8 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoFdmSupports.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoFdmSupports.cpp
@@ -204,14 +204,18 @@ void GLGizmoFdmSupports::render_cursor_circle() const
 
 void GLGizmoFdmSupports::update_model_object() const
 {
+    bool updated = false;
     ModelObject* mo = m_c->selection_info()->model_object();
     int idx = -1;
     for (ModelVolume* mv : mo->volumes) {
         if (! mv->is_model_part())
             continue;
         ++idx;
-        mv->m_supported_facets.set(*m_triangle_selectors[idx].get());
+        updated |= mv->m_supported_facets.set(*m_triangle_selectors[idx].get());
     }
+
+    if (updated)
+        m_parent.post_event(SimpleEvent(EVT_GLCANVAS_SCHEDULE_BACKGROUND_PROCESS));
 }