QFileDialog to only show executable files in Linux

[qlands]

I have a QFileDialog that I want only to select executable files. Here is the code:

QFileDialog selectFile(this,title);
    selectFile.setFilter(QDir::Files | QDir::Executable);
    selectFile.setDirectory(path);
    selectFile.setFileMode(QFileDialog::ExistingFile);
    if (selectFile.exec())
          qDebug() << selectFile.selectedFiles();

QFileDialog selectFile(this,title);
    selectFile.setFilter(QDir::Files | QDir::Executable);
    selectFile.setDirectory(path);
    selectFile.setFileMode(QFileDialog::ExistingFile);
    if (selectFile.exec())
          qDebug() << selectFile.selectedFiles();

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However I can see all files if I run it in Linux. Any idea how to correct it?