GtkDialog mapped without a transient parent

[123newuser]

hi i am using CentOS Linux release 7.9.2009 (Core)
in my Qt application when i open a file to read i get a warning
Gtk-Message: 12:45:22.456: GtkDialog mapped without a transient parent. This is discouraged.
i have spent hours on internet how to fix this but not got any solutions i have understood that i am getting this error because GTK window is not taking the parent which i am passing as "this" (in my case it is Mainwindow)

(attaching my code here)
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
QString fileName = QFileDialog::getOpenFileName(this, "Open the file");
QFile file(fileName);
}

so please suggest a way in which i can fix this warning thanks in advance

[SGaist]

Hi,

IIRC, it comes from the GTK platform theme plugin and nothing you can do about.