message: show only material nodes in list box
diff: @@ -2226,6 +2226,7 @@ void MainWindow::buildWindowMaterialEditor()
  static int currentMaterial = -1;
  std::vector<sg::NodePtr> materialNodes;
  for (auto &mat : baseMaterialRegistry->children())
  + if (mat.second->type() == sg::NodeType::MATERIAL)
  materialNodes.push_back(mat.second);
  if (materialNodes.empty()) {
  ImGui::Text("No materials found");
  