RFR: 4938801: The popup does not go when the component is removed [v6]

[Alexey Ivanov]

On Tue, 29 Jul 2025 11:56:49 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

>> Issue is seen that a popup doesn't get closed when the component that invokes it, gets removed from the parent container.
>> This is because the JPopupMenu does not listen to its invoker liefecycle thereby behaving as a standalone entity after creation.
>> Fix is made to make sure popup listens to its invoker lifecycle by registering its PropertyChangeListener to the invoker and listens to the ["ancestor" property name ], https://github.com/openjdk/jdk/blob/441dbde2c3c915ffd916e39a5b4a91df5620d7f3/src/java.desktop/share/classes/javax/swing/JComponent.java#L4853-L4858 which will become null when removed, wherein we should dispose of the popup
>
> Prasanta Sadhukhan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use named property listener, update test

> Is the PropertyChangeEvent fired _immediately_ as the component is added/removed, or is the notification delayed in an invoke-later somewhere? Because if it's delayed: we can check to make sure the information is still relevant.

Yes, it's fired immediately. See the piece of code in the PR description, I'm quoting here for convenience too:

https://github.com/openjdk/jdk/blob/441dbde2c3c915ffd916e39a5b4a91df5620d7f3/src/java.desktop/share/classes/javax/swing/JComponent.java#L4853-L4858

> There are some (probably "bad") UIs that rebuild the UI constantly: they call container.removeAll() and then re-add child components. The end result is usually that the user doesn't perceive a change because the container is stripped and re-built to resemble its original state.
> 
> But those UIs may suffer under this PR. (That is: as soon as component is removed the popup is hidden, even if that component is immediately re-added.)

In this case, if the UI is rebuilt this way while a popup is displayed on the screen, the popup will be hidden.

Usually, UI is rebuilt in reaction to an event… such as an action (button press, menu selection), so we may expect the popup is already hidden.

> To be clear: I like this PR and have no objection to going forward with it. I think the UI's I'm describing here are badly designed. But it is a potential unintended consequence to consider.

You're right. However, what would be the expected behaviour? Hiding the displayed popup when its owner is removed from the component hierarchy, or ensuring the displayed popup remains visible?

The former looks reasonable enough to me. If it's the latter, then there's no bug to fix and we can just leave the code unmodified.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/26407#issuecomment-3134020173