RFR: 8375070: NPE in Scene.ClickGenerator::preProcess when mouse button is none [v3]

[Christopher Schnick]

On Tue, 13 Jan 2026 09:25:20 GMT, Ambarish Rapte <arapte at openjdk.org> wrote:

>> Christopher Schnick has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Preserve original logic even more
>
> modules/javafx.graphics/src/main/java/javafx/scene/Scene.java line 3721:
> 
>> 3719:                 if (! e.isBackButtonDown()) { counters.get(MouseButton.BACK).clear(); }
>> 3720:                 if (! e.isForwardButtonDown()) { counters.get(MouseButton.FORWARD).clear(); }
>> 3721:                 if (cc != null) {
> 
> Instead of a null check, I would recommend to validate the MouseEvent **e**.
> `counters` does not have an entry for `MouseButton.NONE`, instead of null check below check could fit better:
> `if (e.getButton() == MouseButton.NONE) return;`
> 
> Looks like in this issue scenario this is true: `e.getButton() == MouseButton.NONE && e.getEventType() == MouseEvent.MOUSE_PRESSED`. It would be good to understand why this is happening?

About why this is happening, I saw a reference to JDK-8110944 in the mouse button handling code for the NONE type but the issue is not found for me. Is the bug ID wrong or is that a restricted issue?

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PR Review Comment: https://git.openjdk.org/jfx/pull/2034#discussion_r2685814358