QSpinBox QDoubleSpinBox and style sheets margin shift background

Hi,
When I put a spinbox, apply the following style sheet :
margin-top: 5px;

I get that(see form-spinbox.png)

First with margin 5px top,
Second with margin 5px bottom
third with margin 5px left
fourth with margin 5px right

this not affect QLineEdit or QWidget.
it seems that a margin is applyed to the "background" ...the input value is not affected.

the last show a bug in the down arrow background (sort of background-repeat)