RFR: 8279140: ComboBox can lose selected value on item change via setAll [v2]

[Andy Goryachev]

On Thu, 9 May 2024 09:38:31 GMT, Karthik P K <kpk at openjdk.org> wrote:

>> The `ComboBox` value was not set to previously selected value in the item list change listener when `setAll` method is used to change the items. Fixed the issue by restoring the selection in this case.
>> 
>> Added a unit test to validate the fix.
>> [JDK-8279139](https://bugs.openjdk.org/browse/JDK-8279139) is also fixed with this change and added a unit test for the same.
>
> Karthik P K has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix JDK-8279139

It looks like we have quite a few bugs related to different aspects of ComboBox.  This change is definitely an improvement, as it fixes the scenario described in JDK-8279140.

This PR changes parts of the code that fixed JDK-8087838.  While I don't see a regression in respect to JDK-8087838, I do see a different behavior with and without this fix in JDK-8090221, using the test app there (to be specific, with the fix in this PR, the tester in JDK-8090221 continues to display the selected item in the combo box even though the output shows `Selected Item After: null`

Do you think that JDK-8090221 scenario is a different case and should be addressed separately?

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PR Comment: https://git.openjdk.org/jfx/pull/1452#issuecomment-2111241863