RFR: 8370446: Support dialogs with StageStyle.EXTENDED

[Michael Strauß]

On Thu, 23 Oct 2025 15:18:41 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> Adds the `Dialog.headerBar` property, which allows developers to specify a custom `HeaderBar` when the dialog uses the `EXTENDED` stage style. The property is ignored for all other stage styles.
>
> modules/javafx.controls/src/main/java/javafx/scene/control/Dialog.java line 594:
> 
>> 592:      * @since 26
>> 593:      */
>> 594:     private ObjectProperty<HeaderBar> headerBar;
> 
> Since this is a preview feature, it needs to be documented and handled as such.

Good point. This requires documenting all property methods individually, instead of relying on the javadoc tool to do it automatically (as the `@deprecated` annotation is not carried over). I'll revert this to a property field doc once this feature is finalized.

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PR Review Comment: https://git.openjdk.org/jfx/pull/1943#discussion_r2455894309