RFR: 8319779: SystemMenu: memory leak due to listener never being removed [v8]

[Johan Vos]

On Thu, 11 Jan 2024 11:45:02 GMT, Johan Vos <jvos at openjdk.org> wrote:

>> A listener was added but never removed.
>> This patch removes the listener when the menu it links to is cleared. Fix for https://bugs.openjdk.org/browse/JDK-8319779
>
> Johan Vos has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Revert some of the conditional bindings.
>   Clear menu construction when an menuitem that is a menu needs to be removed
>   Add a test for the latter

A few things about the latest commit:

1. The usage of the `active` property caused regression: the memoryLeak test that was introduced in the fix for JDK-8318841 now failed. A number of listeners were hard referenced from the `active` property.
The complexity is that there are different entry points by which a listener should be removed. What we try to do in this PR, is making sure we remove listeners after a defocus/focus operation that would otherwise stay referenced. A focus operation will result in GlassSystemMenu.setMenus() being called. 
I reverted some of the dependencies on the `active` property, and kept those that were directly created as a consequence of the setMenus call.

2. I added a test that demonstrates the issue when not removing menu's completely inside the listener, as reported by @jperedadnr and this issue is fixed as well now.

3. All tests now pass, but I noticed that in some cases, the systemtests do not correctly work with the application lifecycle management (see https://mail.openjdk.org/pipermail/openjfx-dev/2024-January/044516.html). For now, I consider this anomaly to be independent from JDK-8319779

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

PR Comment: https://git.openjdk.org/jfx/pull/1283#issuecomment-1887227196