QComboBox does not show popup list when over a QVTKOpenGLNativeWidget and fullscreen window

Support
1

Hello,

I’m trying to embed a 3D model into a Qt window. For that, I’m using the QVTKOpenGLNativeWidget. However, I have to add also a QComboBox in a overlay. The problem is that the QComboBox popup list does not show if the window is fullscreen. The same also happens if I set tooltips.

For this project I’m using Qt 6.8.3, VTK 9.5.2, Windows 11 x64 and Visual Studio 2022.

Here I’m attaching a minimal reproducible code. Do you have any suggestion for solving the problem ?

Thanks a lot in advance :slightly_smiling_face:

#include <QApplication>
#include <QMainWindow>
#include <QStackedLayout>
#include <QComboBox>
#include <QLabel>
#include <QVBoxLayout>
#include <QFrame>

#include <QVTKOpenGLNativeWidget.h>
#include <vtkGenericOpenGLRenderWindow.h>
#include <vtkRenderer.h>

int main(int argc, char* argv[]){
    QApplication app(argc, argv);

    QMainWindow window;
    QWidget* central = new QWidget;
    window.setCentralWidget(central);

    QStackedLayout* stacked = new QStackedLayout(central);
    stacked->setStackingMode(QStackedLayout::StackAll);

    // QFrame container for VTK widget
    QFrame* frame = new QFrame;
    frame->setFrameShape(QFrame::Box);
    frame->setLineWidth(2);

    QVBoxLayout* frameLayout = new QVBoxLayout(frame);
    frameLayout->setContentsMargins(0, 0, 0, 0);
    frameLayout->setSpacing(0);

    // VTK Widget
    auto vtkRenderWidget = new QVTKOpenGLNativeWidget;
    auto renderWindow = vtkSmartPointer<vtkGenericOpenGLRenderWindow>::New();
    auto renderer = vtkSmartPointer<vtkRenderer>::New();
    renderWindow->AddRenderer(renderer);
    vtkRenderWidget->setRenderWindow(renderWindow);
    renderer->SetBackground(0.1, 0.1, 0.2);

    frameLayout->addWidget(vtkRenderWidget);
    stacked->addWidget(frame);

    // Overlay with QComboBox
    QWidget* overlay = new QWidget;
    overlay->setStyleSheet("background: rgba(255, 0, 0, 40);");
    stacked->addWidget(overlay);

    QVBoxLayout* vbox = new QVBoxLayout(overlay);
    QLabel* label = new QLabel("Select value:");
    QComboBox* combo = new QComboBox;
    combo->addItems({ "Value 1", "Value 2", "Value 3" });
    vbox->addWidget(label);
    vbox->addWidget(combo);
    vbox->addStretch();

    stacked->setCurrentIndex(1);

    window.showFullScreen();
    //window.resize(800, 600);
    //window.show();

    return app.exec();
}