RFR: 8350976: MenuBarSkin: exception initializing in a background thread [v2]

[Andy Goryachev]

On Wed, 5 Mar 2025 18:19:53 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

>> Allows MenuBar to be created in a background thread by delaying MenuBarSkin::rebuildUI() call until after the MenuBar becomes a part of the scene graph.
>
> Andy Goryachev 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 six additional commits since the last revision:
> 
>  - Merge remote-tracking branch 'origin/master' into 8350976.menubarskin.thread.safety
>  - spelling
>  - use system menu
>  - cleanup
>  - possible fix
>  - test

`javafx.graphics/com.sun.glass.ui.Application.checkEventThread()` throws an IllegalStateException since 2013, and probably earlier than that.

The only way this functionality is suppressed is when `glass.disableThreadChecks` system property is set to `true`.

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PR Comment: https://git.openjdk.org/jfx/pull/1727#issuecomment-2770249357