Frame/ JFrame with option setUndecorated(true) and setState(Frame.ICONIFIED) does not iconify the window, hence window state event is not produced.
Platform specific: Yes, only on macos
Regression: No, issue exists on 11.0.1 also.
Issue is not observed on: jdk8u and jdk10.0.2/jdk10..0.1.
Attached Test code to reproduce the issue.