On Thu, 5 Sep 2024 20:32:07 GMT, Damon Nguyen <[email protected]> wrote:
>> In a JComboBox, if the user opens the dropdown list and clicks and holds the
>> down-button, then ALT-TABs to switch focus, when the user re-focuses the
>> frame with the JComboBox and opens the dropdown list again, the list will
>> still be scrolling even though the down-button isn't pressed.
>>
>> This isn't OS or L&F specific, although Aqua L&F does not have any
>> directional arrows in the dropdown list (and is thus exempt). This led me to
>> believe it could be handled in BasicComboBoxUI where focusLost and focusGain
>> are used or isPopupVisible but the scroll behavior cannot be altered here.
>> Likewise for BasicComboPopup where `autoscroll` is used. However, this
>> behavior isn't related to autoscroll and is actually found in the JScrollbar
>> of the JScrollpane inside of the JComboBox. The timer for the scroll action
>> starts but is never stopped if focus is lost, so a new listener is created
>> and used. The proposed solution uses `KeyboardFocusManager` to track the
>> focus owner. The listener stops the `scrollTimer` when the `focusOwner`
>> property is changed. With this change, the list no longer automatically
>> scrolls when re-focused and instead opens normally.
>>
>> The included test is manual due to the need to confirm that the list still
>> scrolls after ALT-TABing. The L&F is set to Metal since it is the
>> cross-platform lookandfeel and has directional buttons for the JScrollPane
>> list.
>
> Damon Nguyen has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Review comments
test/jdk/javax/swing/JComboBox/JComboBoxScrollFocusTest.java line 53:
> 51:
> 52: public static void main(String[] args) throws Exception {
> 53:
> UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
This fix is not Metal L&F specific right?
test/jdk/javax/swing/JComboBox/JComboBoxScrollFocusTest.java line 72:
> 70: }
> 71: frame.add(combobox);
> 72: frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
`frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);` Not required I guess.
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PR Review Comment: https://git.openjdk.org/jdk/pull/20845#discussion_r1800924824
PR Review Comment: https://git.openjdk.org/jdk/pull/20845#discussion_r1800926149
