RFR: 8348100: Tooltips cannot be instantiated on background thread [v3]

[Kevin Rushforth]

On Fri, 7 Feb 2025 19:16:48 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

>> ## Root Cause
>> navigating up the parent hierarchy during CSS processing in a background thread encounters a null parent, causing the NPE.  The null parent comes from a static Toolkit.BEHAVIOR field.
>> 
>> ## Solution
>> avoid that code path if not in the fx application thread.
>
> Andy Goryachev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   behavior

Looks good now. I confirm that the new test fails reliably without the fix and passes with the fix.

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Marked as reviewed by kcr (Lead).

PR Review: https://git.openjdk.org/jfx/pull/1696#pullrequestreview-2602617890