RFR: 8370498: Improve how Node detects whether a layout property change requires a new layout pass [v4]

[Andy Goryachev]

On Mon, 27 Oct 2025 14:44:44 GMT, John Hendrikx <jhendrikx at openjdk.org> wrote:

>> This new check is much more accurate to detect whether a parent is currently laying out its children. The previous code almost never worked, resulting in additional unnecessary layouts.
>
> John Hendrikx has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Rename test

First of all, I would like to thank you John for looking into the layout problems.  We've got these long standing issues that are very difficult to debug and fix.

I think this is valuable work as it definitely improves the platform, so Danke schön.

The reason I asked about tests and test scenarios is the possibility of regression.  Case in point - with this PR, on macOS with an external monitor at scale=1:

<img width="1184" height="340" alt="Image" src="https://github.com/user-attachments/assets/f55f0c01-c59a-49b5-8fc6-91470524eb9a" />

I would second @johanvos in suggesting that the regression is what we should be guarding against, and perhaps expanding the tests.

modules/javafx.graphics/src/main/java/javafx/scene/Parent.java line 1290:

> 1288:                     layoutChildren();
> 1289:                 }
> 1290:                 finally {

minor suggestion:
`} finally {`

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PR Review: https://git.openjdk.org/jfx/pull/1945#pullrequestreview-3385140013
PR Review Comment: https://git.openjdk.org/jfx/pull/1945#discussion_r2466840973