RFR: 8371657: [macosx] Programmatically selecting/deselecting List item triggers an ItemEvent

[Sergey Bylokhov]

On Wed, 26 Nov 2025 17:04:30 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

>> When I was working on [JDK-8369327](https://bugs.openjdk.org/browse/JDK-8369327) I got a suggestion to update the code that disables unnecessary events:
>> https://github.com/openjdk/jdk/pull/27682#discussion_r2487686109
>> 
>> After checking that code more closely, I found that it does not work in all cases. The checks were first added in [JDK-7125456](https://bugs.openjdk.org/browse/JDK-7125456). It looks like only the case for the select method was fixed. Other cases still cause unnecessary events, and even more events happen when trying to add multi selection mode: https://github.com/openjdk/jdk/pull/27682#issuecomment-3487434403
>> 
>> So I made a new bug for this issue and fixed it separately.
>> 
>> The [spec](https://github.com/openjdk/jdk/blob/8531fa146be1da5e96c0f23091882a27c67d7893/src/java.desktop/share/classes/java/awt/List.java#L899):
>> 
>>   * Adds the specified item listener to receive item events from
>>   * this list.  Item events are sent in response to user input, but not
>>   * in response to calls to {@code select} or {@code deselect}.
>> 
>> 
>> The new test checks most of the methods in the `java.awt.List` class. It passes on linux/windows, confirming that the same behavior is implemented in other toolkits (unfortunately on linux it is not stable enough so I had to problemlist it due to [JDK-8201307](https://bugs.openjdk.org/browse/JDK-8201307)). The test only checks for programmatic changes to the list. I am sure that if I change it to test mix of programmatic/user changes it will fail. I will work on that in a follow up bug.
>> 
>> @aivanov-jdk @azvegint please take a look
>
> test/jdk/java/awt/List/NoEvents/ProgrammaticChange.java line 103:
> 
>> 101:         verify();
>> 102: 
>> 103:         // "makeVisible" may change the current selection
> 
> I wonder how `makeVisible` can change the current selection. I'd say it's a bug, if calling `makeVisible` changes the current selection.

As of now, it should not change. However, this is lwawt, which uses the active swing l&f, and I do not see a reason why someone could not change that based on a design choice.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28245#discussion_r2566930453