RFR: 8372453: [macOS] Iconifying owner may not iconify owned window

[Kevin Rushforth]

On Tue, 25 Nov 2025 17:26:36 GMT, Martin Fox <mfox at openjdk.org> wrote:

> In the macOS glass code an owned window is referred to as a child window and its owner is referred to as the parent. When a parent is iconified the glass code "iconifies" its children which is to say it hides them. Under the right circumstances the children may get ordered back to the front and made visible almost immediately.
> 
> Details are in the bug report but when a window is iconified it may trigger the OS to notify every window that its NSScreen has changed (yes, this is weird). This causes reorderChildWindows to be called on the newly iconified parent and the process of re-ordering the child windows can cause hidden windows to be made visible. For some reason the NSScreen strangeness only happens if "System Settings > Desktop & Dock > Minimize windows into application icon" is turned OFF. This is not the first time we've encountered this, see [JDK-8353902](https://bugs.openjdk.org/browse/JDK-8353902)
> 
> This PR fixes the problem in two ways. If reorderChildWindows is called on an iconified window it does nothing. If one of the child windows is hidden it is not re-ordered since that might make it visible.

I can make this happen consistently if another JavaFX program is running (whether or not it is iconified) when I run the OwnerIconify test program. HelloModality also fails.

With your patch it looks like everything is running fine. I'll do some more testing and then will approve it if I don't see any problems.

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PR Comment: https://git.openjdk.org/jfx/pull/1985#issuecomment-3577321044