diff --git a/Polyhedron/demo/Polyhedron/MainWindow.cpp b/Polyhedron/demo/Polyhedron/MainWindow.cpp
index 5344f2e6c8d..9fcb2ffb6c9 100644
--- a/Polyhedron/demo/Polyhedron/MainWindow.cpp
+++ b/Polyhedron/demo/Polyhedron/MainWindow.cpp
@@ -2104,6 +2104,8 @@ void MainWindow::insertActionBeforeLoadPlugin(QMenu* menu, QAction* actionToInse
 void MainWindow::colorItems()
 {
   std::size_t nb_files = scene->selectionIndices().size();
+  if(nb_files<2)
+    return;
   std::vector<QColor> colors_;
   colors_.reserve(nb_files);
   compute_color_map(scene->item(scene->selectionIndices().last())->color(),