RFR: 8319779: SystemMenu: memory leak due to listener never being removed [v21]

[John Hendrikx]

On Tue, 9 Jul 2024 09:06:58 GMT, Johan Vos <jvos at openjdk.org> wrote:

>> A listener was added but never removed.
>> This patch removes the listener when the menu it links to is cleared. Fix for https://bugs.openjdk.org/browse/JDK-8319779
>
> Johan Vos has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Allow scheduled runnables to be executed on the FX App Thread before checking for exceptions.

LGTM, note that I couldn't test this as I don't have access to a Mac, but I didn't see a problem on Windows with these changes.

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Marked as reviewed by jhendrikx (Reviewer).

PR Review: https://git.openjdk.org/jfx/pull/1283#pullrequestreview-2166059441