<Swing Dev> [9] Review request for 8033069: mouse wheel scroll closes combobox popup

[Alexey Ivanov]

Hi Sergey,

The changes in BasicPopupMenuUI are similar to handling mouse events for 
JMenu. The popup stays open if user rotates wheel over combo box that 
opened the popup but the popup will be canceled if wheel is rotated over 
another combo box or any other component.

The client property "doNotCancelPopup" is set for each combo box because 
MOUSE_PRESS logic is in BasicComboPopup.Handler.mousePressed. If you 
click another combo box, it will open its own popup which automatically 
hides the popup that was visible.

In case of MOUSE_WHEEL, combo box over which mouse wheel is rotated 
should close the popup of another combo box that opened the popup; and 
it should do nothing if its own popup is open. Moving this logic into 
JComboBox MouseWheelListener seems too complicated.


As for user-installed MouseWheelListener on JComboBox, of course 
mouseWheelMoved is called but MouseWheelEvent is already marked 
consumed. It might have a negative effect on user code if they check 
isConsumed() flag. If the event is not consumed, the popup will be closed.

Regards,
Alexey

On 06.05.2015 22:28, Sergey Bylokhov wrote:
> Hi, Alexey.
> The changes in the BasicPopupMenuUI does not look clear, I am not sure 
> but probably it will be better to implement it in the same way as for 
> MOUSE_PRESSED(via UIManager property)? It will add an additional 
> configuration possibility.
> Can you also confirm that the case when the user install mouse wheel 
> listener to the JComboBox still works.
>
> On 06.05.15 16:30, Alexey Ivanov wrote:
>> Hello Swing team,
>>
>> Could you please review the fix:
>>     bug: https://bugs.openjdk.java.net/browse/JDK-8033069
>>     webrev: http://cr.openjdk.java.net/~aivanov/8033069/jdk9/webrev.00/
>>
>> Description:
>> If you rotate mouse wheel when combo box popup is open, the popup 
>> gets closed.
>>
>> The fix is to always consume MOUSE_WHEEL event.
>>
>> There are two regression tests for the cases where popup has vertical 
>> scroll bar and does not have scroll bar.
>>
>> Thanks,
>> Alexey
>
>
> -- 
> Best regards, Sergey.

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