Padding in QToolTip stylesheet causes text to show incorrectly

#include <QtGui/QApplication>
#include "mainwindow.h"
#include <QToolButton>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QToolButton button;
    button.setStyleSheet( "QToolTip {\
                          padding: 6px;\
          border: 1px solid rgb(199, 202, 204);\
          background-color: rgb(227, 243, 252);\
          color: rgb(64, 64, 66);\
}");
    button.setToolTip("my tooltip");
    button.show();

    return a.exec();
}