plbl = new QLabel();
    plbl->setGeometry(210, 0, 26, 16);
    plbl->setAlignment(Qt::AlignRight);
    plbl->setAlignment(Qt::AlignVCenter);
    plbl->setStyleSheet("border: 0px; background-color:rgba(0,0,0,0%);");
    plbl->show();

plbl->setStyleSheet("QLabel {border: 0px; background-color:rgba(0,0,0,0%);}");