On MacOSX cycling through windows of an App does not work. I've attached a simple testcase. The test starts 5 JFrames. When you try to cycle through the windows with [CMD + `] it will only toggle between the last 2 frames but you won't reach any other.
This used to work with 1.8.0_121. In higher JDKs (including current 11 and 12), the issue can be reproduced