RFR: 8370446: Support dialogs with StageStyle.EXTENDED [v3]

[Kevin Rushforth]

On Fri, 7 Nov 2025 01:54:56 GMT, Michael Strauß <mstrauss at openjdk.org> wrote:

>> Adds the `DialogPane.headerBar` property, which allows developers to specify a custom `HeaderBar` when the dialog uses the `EXTENDED` stage style.
>
> Michael Strauß has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains seven additional commits since the last revision:
> 
>  - documentation
>  - Merge branch 'master' into feature/extended-dialog
>  - move HeaderBar to DialogPane
>  - document/verify preview feature
>  - Ensure that DialogPane is always attached to Scene
>  - Lazily initialize Dialog.headerBar
>  - Support dialogs with StageStyle.EXTENDED

API changes look good. The code change look good, although I left an inline question about one of the changes (since it would impact all stage styles, not just EXTENDED).

You can create the CSR now.

modules/javafx.controls/src/main/java/javafx/scene/control/DialogPane.java line 221:

> 219:         headerTextPanel = new GridPane();
> 220:         headerTextPanel.setVisible(false);
> 221:         headerTextPanel.setManaged(false);

Why was this change needed? At first glance it seems unrelated to supporting an (optional) header bar.

modules/javafx.controls/src/main/java/javafx/scene/control/DialogPane.java line 228:

> 226:         contentLabel = createContentLabel("");
> 227:         contentLabel.setVisible(false);
> 228:         contentLabel.setManaged(false);

Same question here.

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PR Review: https://git.openjdk.org/jfx/pull/1943#pullrequestreview-3455010645
PR Review Comment: https://git.openjdk.org/jfx/pull/1943#discussion_r2519469531
PR Review Comment: https://git.openjdk.org/jfx/pull/1943#discussion_r2519470170