Font Alignment issues on MacOSX 10.8.5

Hi,
I need to use a different font than the default font on every Widget. But if I do the vertically alignment of the text seems to be wrong. I created an example to show you the issue:

Attachment 10117

Here is the key code:

Code:

---

#include "mainwindow.h"
#include <QApplication>
 
int main(int argc, char *argv[])
{
	QApplication a(argc, argv);
	a.setStyleSheet("*{ \n"
			"	font: 14px Helvetica;\n"
			"}");
	MainWindow w;
	w.show();
 
	return a.exec();
}

---

What am I doing wrong or how can I fix this issue? To me it looks like the font metrics are not calculated properly. (I know there was a similar issue on 10.9 even with the default font...)
BTW: I compiled my own version of Qt with the following config options:
-opensource -fontconfig

And this issue occurs with Qt 4.8.5 and 5.2

Thanks in advance
Timo