How to create submenus (or multiple command UIs)

I have some UI

Everything into the Command UI is a Imgui::Button inside the callback

    ImGui::InputInt("Radius", &radius);

    ImGui::SameLine();

    //
    // Button
    if (ImGui::Button("Max Curvature"))
    {
        // get mesh
        polyscope::registerSurfaceMesh("mesh", V, F);
        
        // Compute curvature directions via quadric fitting
        MatrixXd PD1, PD2;
        VectorXd PV1, PV2;
        std::vector<Index> bv = {};
        
        igl::principal_curvature(V, F, PD1, PD2, PV1, PV2, bv, radius);
        
        polyscope::getSurfaceMesh("mesh")
            ->addVertexScalarQuantity("Max Curvature", PV1,
                                      polyscope::DataType::SYMMETRIC);
        
    }

pretty standard. Now I'd like to add the "radius" input inside the button scope, so that when I press the button all the relevant data is presented to the user.
Of course, if I simply put the input widget code inside the button one the input widget is just show for an instant then deleted, as the callback runs over and over.
The best option would be to create a separate sub-UI, possibly opening down below the command UI itself. Or to create multiple command UIs.
Is there a way?
Thank you

Commencez par le callback de Command UI et l’utilisation de ImGui::InputInt et ImGui::Button présentée dans l’issue. Déterminez comment un champ de saisie de rayon persistant ou un sous-menu séparé pourrait rester visible entre les invocations du callback, et définissez quelle interaction doit être considérée comme terminée ; l’issue ne nomme aucun fichier ni test.