QDockWidget title does not change with QApplication::setFont(vFont)

When using the following code to change the font in our application, the font changes in all widgets except in the title of QDockWidget. The contents of the QDockWidget are changed correctly, but not the title.

```
QApplication::setAttribute(Qt::AA_UseStyleSheetPropagationInWidgetStyles, true);
QApplication::setFont(vFont);
```