As the title says. Currently, undecorated Stages on Windows just instantly disappear/appear when iconified/maximized. This looks quite unprofessional.
In addition to this, undecorated Stages cannot be minimized/restored by clicking the taskbar-icon, without some JNA hackery. For more details, see this StackOverflow post: https://stackoverflow.com/questions/51008461/javafx-minimizing-maximing-undecorated-stage-with-animations
