For the issue of 'Cycling through windows (JFrames) does not work with keyboard shortcut' on macosx, the fix provided by JDK-8212007, JDK-8212180 as a backport on 8u202 and 11.0.2 is only partially working.
Attached is a test which opens up Multiple JFrames with a combobox in it.
Execute the test with the build with the fix
1) Press CMD + ` keys multiple times. Toggling of active frame between 3,2,1 occurs as expected.
This is the expected fix and the behaviour should be seen consistently always.
2) Now with Frame 3 being active click on Frame 2 to make it active.
Expected : Toggling of active frame between 3,2,1
Actual: Toggling of active frame between 3 and 2 only.
Now, try the same by randomly selecting any one frame and then pressing CMD +` key the cycling ceases to happen across all the 3 frames.