message: collapse scene graph tree by default
diff: @@ -512,7 +512,7 @@ namespace ospray {
  guiFindNode();
  guiTransferFunction();
  - if (ImGui::CollapsingHeader("SceneGraph", "SceneGraph", true, true))
  + if (ImGui::CollapsingHeader("SceneGraph", "SceneGraph", true, false))
  guiSGTree("root", scenegraph);
  ImGui::End();
  