Please run the test ('Test.java'), push "open" button on a frame, then "open" button on a window; a dialog will appear. Push "close" button on the dialog, the focus will not return to the frame.
If open/close the dialog once more, the frame will gain the focus.

Tested on Solaris 11, JDK 9 b13

The frame will also gain the focus if run the example on Linux or Windows OS (tested on Windows 7, Ubuntu 14.04).