RFR: 8306121: Scene not rendered initially when changing scenes after fix for JDK-8296621 [v20]

[Kevin Rushforth]

On Tue, 6 Jun 2023 01:09:36 GMT, Thiago Milczarek Sayao <tsayao at openjdk.org> wrote:

>> I replicated the fix on #1054 on Linux.
>> 
>> Also fixes [Monocle: Stage no longer gets focus after fix for JDK-8296621](https://bugs.openjdk.org/browse/JDK-8304734)
>
> Thiago Milczarek Sayao has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Insert copyright

Thanks for the explanation about why you had to change the tests.

The latest fix looks good. All my testing is green.

Running the new `StartIconified` manual test reveals two problems:
1. On Windows there is a brief flash where the window is visible before it is iconified -- we should file a P4 bug
2. On macOS 13 (not sure about 12) the Stage is not iconified at all -- this is tracked by [JDK-8305675](https://bugs.openjdk.org/browse/JDK-8305675)

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Marked as reviewed by kcr (Lead).

PR Review: https://git.openjdk.org/jfx/pull/1110#pullrequestreview-1462939278