RFR: 8325900: Emit a warning on macOS if AWT has set the NSAppearance

[Kevin Rushforth]

On Wed, 14 Feb 2024 21:09:39 GMT, Michael Strauß <mstrauss at openjdk.org> wrote:

> Platform preferences detection doesn't pick up effective macOS system preferences if AWT owns the NSApplication and has set its NSAppearance to a fixed value.
> 
> The workaround is to set the system property "apple.awt.application.appearance=system".
> 
> If this property is not set, the following warning will be emitted if a JavaFX application attempts to use the platform preferences API:
> 
> 
> WARNING: Reported preferences may not reflect the macOS system preferences unless the sytem
> property apple.awt.application.appearance=system is set. This warning can be disabled by
> setting javafx.preferences.suppressAppleAwtWarning=true.

I'll take a closer look tomorrow or Friday. This might need to be refactored a bit so we don't call directly into glass from `javafx.application.Platform`.

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PR Comment: https://git.openjdk.org/jfx/pull/1367#issuecomment-1944900417