how i want flat Drop-down Button for ComboBox ?

[pavanbarot]

Finally i done with style sheet like below:

QComboBox::drop-down:button{
background-color: rgb(234,234,234);
}

for all drop-down button like (QDateTime, QComboBox.....etc)
*::drop-down:button{
background-color: rgb(234,234,234);
}