Android QT 5.7 Widgets do not dim screen on modal dialog

On Android (arm) QMessageBox dims (darkens) the parent widget during exec() but QDialog does not. Tested with following code:

QDialog *d2;
d2=new QDialog(this);
d2->setModal(true);
d2->setFixedSize(200,200);
QPalette Pal(palette());
Pal.setBrush(QPalette::Window,QColor(255,255,200,128));
d2->setPalette(Pal);
QLabel *label;
label=new QLabel(d2);
label->setText("Hello Putin");
d2->exec();

I attach how it looks with Desktop, and the background is dimmed.
I also attach the screen of the Samsung S5 , where the background is NOT dimmed, which is a bug.

I need to know if you are going to fix this, or I should implement my own dimming on android.