On Windows, usage of USER_ATTENTION_WINDOW depends on state setting order

On MS Windows we support now Taskbar.Feature.USER_ATTENTION_WINDOW.
For instance, the attached code works well: after a second, an icon on the taskbar starts flashing.
However if you change the order of these two lines, it doesn't work any more:
        f.setState(Frame.ICONIFIED);
        f.setVisible(true);