RFR: 8356594: JSplitPane loses divider location when reopened via JOptionPane.createDialog() [v2]

[Prasanta Sadhukhan]

On Tue, 20 May 2025 04:34:36 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

>> The issue is when a JSplitPane is embedded inside a lazily-initialized panel, and this panel is displayed using a dialog created via JOptionPane.createDialog(), the divider location is not preserved when reopening the dialog. 
>> This is because when we added support for ComponentOrientation for JSplitPane, even though the left and right compoent is drawn the divider location is not set and was set to initial value and not to the value set by user.
>> Fixed by setting the divider location before rendering the left and right components..
>
> Prasanta Sadhukhan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Click position fixed..L&F iteration

setDividerLocation call is needed as when `BasicSplitPaneUI$BasicHorizontalLayoutManager.layoutContainer` is called to layout, it checks [`doReset ` and `dividerLocationIsSet` ](https://github.com/openjdk/jdk/blob/91194517c75a96fe7bcc2dcf5e9c42af9cf5975a/src/java.desktop/share/classes/javax/swing/plaf/basic/BasicSplitPaneUI.java#L1423-L1437)

Now, when `JSplitPane.setComponentOrientation `calls `setLeftComponent `it sets `doReset `to true (in `BasicSplitPaneUI.addLayoutComponent`) so `resetToPreferredSizes` is called when we open the dialog the 2nd time. so it causes this issue

Now if we call setDividerLocation it will set [dividerLocationIsSet](https://github.com/openjdk/jdk/blob/91194517c75a96fe7bcc2dcf5e9c42af9cf5975a/src/java.desktop/share/classes/javax/swing/plaf/basic/BasicSplitPaneUI.java#L1029) so even if `doReset `is true, it will not call `resetToPreferredSizes` but sets correct [divider location](https://github.com/openjdk/jdk/blob/91194517c75a96fe7bcc2dcf5e9c42af9cf5975a/src/java.desktop/share/classes/javax/swing/plaf/basic/BasicSplitPaneUI.java#L1436)

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PR Comment: https://git.openjdk.org/jdk/pull/25294#issuecomment-2897083731