Shows gray background of application after the resize application window

[yhodage]

Hi ,

i am creating the hoops widget from Qwidget. i am transferring the my application from 3.0 to 4.8 qt.
i have seen that the same code is not working in 4.8 .
whenever i resize my application window it shows first hoops background and after that it shows the gray background.
ex
class HoopsWidget:public QWidget

i have set the some setting in the HoopsWidge constructor but it does not work
setAttribute(Qt::WA_TranslucentBackground);
setAttribute(Qt::WA_NoSystemBackground);
setBackgroundMode (Qt::NoBackground);

this problem is not occur in qt 3.0 library. but on qt 4.8 same code is showing the above mentioned behavior.
Please help me as i am stuck with this problem

Thanks

[IamSumit]

Try this,
setAttribute( Qt::WA_TranslucentBackground, true );
setAttribute(Qt::WA_NoSystemBackground, true);
setBackgroundMode (Qt::NoBackground, true);