Problem with QToolButton + stylesheet

Hi everyone:
I am new in QT, and I have met a problem that when a QToolButton with sub-menu and menu-button is styled with border in QSS, QT will paint the text and icon in the middle of the whole button (the repaint rect includes the menu-button), For example, I set the stylesheet like this:

Code:

---

QToolButton:hover
{
    border: 2px solid;
    background-color: red;
}
 
QToolButton::menu-button:hover
{
    border: 2px solid green;
    background-color: red;
}

---

and when you hovering the QToolButton, the text and icon will move to the middle of the whole button instead of the left part, but if border is set to be "none", it works well

I don't know if I have styled the QToolButton in the right way,
so, is there a solution to this? or how can I get a buttons with down-menu just like those in MS office 2007 ?