QGraphicsDropShadowEffect not working properly in QLable

I was trying to add shadow effect in the qlabel using QGraphicsDropShadowEffect. so i added the effect like this .

Code:

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QGraphicsDropShadowEffect* effect = new QGraphicsDropShadowEffect();
 effect->setBlurRadius(0); 
effect->setColor(QColor(255, 0, 0)); 
effect->setOffset(1,1);
 label1->setGraphicsEffect(effect);

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but the effect is looking weird as for other widget like spinbox it is working proper .

Attachment 10045 here the shadow is coming for the whole QLabel and not for the text in qlabel .

the right one is a qspinbox , it works properly for it but for qlable ,it looks odd. it behaves same as for all the labels in the parent .

but if i take the code and make a sample application it works properly ..

the sample app

Code:

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QApplication app(argc,argv);
    QMainWindow* window = new QMainWindow();
    QWidget* centralWidget = new QWidget();
 
    QSpinBox *spinIt = new QSpinBox;
     QGridLayout *gridLayout = new QGridLayout;
 
     centralWidget->setLayout(gridLayout);
    window->setCentralWidget(centralWidget);
 
    window->setWindowTitle("QLabel With Shadow");
    QSizePolicy sizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
    QLabel* label = new QLabel();
    sizePolicy.setHeightForWidth(label->sizePolicy().hasHeightForWidth());
    label->setSizePolicy(sizePolicy);
    label->setMinimumSize(QSize(0, 0));
    label->setMaximumSize(QSize(16777215, 16777215));
    label->setStyleSheet(QString::fromUtf8("font-size: 12px,0.2em;                          \n"
                                           "font-family: Segoe Regular;  \n"
                                           "color: rgb(0, 0, 0);"));
    label->setText(QApplication::translate("EyGuiProgresColorUi", "Contrast", 0, QApplication::UnicodeUTF8));
 
    gridLayout->addWidget(spinIt, 0, 2, 1, 1);
     gridLayout->addWidget(label, 0, 0, 1, 1);
    QGraphicsDropShadowEffect* effect = new QGraphicsDropShadowEffect();
    effect->setBlurRadius(0);
    effect->setColor(QColor(255, 0, 0));
    effect->setOffset(1,1);
    label->setGraphicsEffect(effect);
 
    window->show();
 
    return app.exec();

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this sample application gives me what i require Attachment 10046 but not in my main application .
please help me what i might doing wrong ..?