RFR: 6318027: BasicScrollBarUI does not disable timer when enclosing frame is disabled. [v4]

[Sergey Bylokhov]

On Thu, 15 Aug 2024 07:26:28 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

>> Issue is
>> BasicScrollBarUI.ArrowButtonListener starts a timer in mousePressed(), and stops it in mouseReleased(). If the frame containing the scrollbar is disabled between the MOUSE_PRESSED and the MOUSE_RELEASED events, the mouseReleased() method is never called. If the frame is then re-enabled, the still-running timer causes it to scroll all the way to the end.
>> Fix is to check if [ArrowButtonListener.handledEvent](https://github.com/openjdk/jdk/blame/ee839b7f0ebe471d3877cddd2c87019ccb8ee5ae/src/java.desktop/share/classes/javax/swing/plaf/basic/BasicScrollBarUI.java#L1567) is still set when ActionEvent is processed then stop the timer and reset this variable.
>> 
>> CI testing is green and also SwingSet2 JScrollPane scrolling with this modification..
>
> Prasanta Sadhukhan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Stop the timer if frame is disabled

>BasicScrollBarUI.ArrowButtonListener starts a timer in mousePressed(), and stops it in mouseReleased(). If the frame containing the scrollbar is disabled between the MOUSE_PRESSED and the MOUSE_RELEASED events, the mouseReleased() method is never called. If

What happens if you make the scrollbar invisible in this case?

src/java.desktop/share/classes/javax/swing/plaf/basic/BasicScrollBarUI.java line 1618:

> 1616:                 if (parent instanceof javax.swing.JFrame par) {
> 1617:                     if (!par.isEnabled()) {
> 1618:                         ((Timer)e.getSource()).stop();

Is the "TImer" always the source for the event?

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PR Comment: https://git.openjdk.org/jdk/pull/20346#issuecomment-2294449988
PR Review Comment: https://git.openjdk.org/jdk/pull/20346#discussion_r1720473148