RFR: 8359108: Mac - When Swing starts First, native application menu doesn't work for JavaFX

[Florian Kirmaier]

On Wed, 18 Jun 2025 20:58:20 GMT, Pabulaner IV <duke at openjdk.org> wrote:

> This pull request fixes the system menu bar on Mac when combining windows of Swing and JavaFX.
> 
> The first issue was to get the native menu bar working simultaneously on Swing and JavaFX, which was done by just returning always true inside the supportsSystemMenu method.
> 
> The second issue was to remove all system menu items installed by a swing window. This was fixed by checking the system menu bar every time an item is inserted or removed and removing all menu items that are not owned by JavaFX. This check is done on every insert and remove as JavaFX does not have a clear method inside the MenuBarDelegate class that could be called every time the window gets the focus.
> 
> I tested the fix with two Swing and two JavaFX windows that are run inside the same application and it works without any errors.
> 
> Co-Author: @FlorianKirmaier

The model we are trying to have here is quite simple.

**Background**
When a Window/Toolkit gets focused, it defines which menus should be shown.
This is done by removing the old menus, and adding their own.
This is basically, what the OS does, when you switch from Application A to B, just inside one process.

Actually, we only wanted to make the JavaFX menu work when Swing/AWT was started first.
But as far as we see, our solution also makes all combinations work.

**Test**
What is definitely missing, which we will add, are unit tests.
We have already investigated - there is an Apple Command line API, which allows us to read out which menus are currently shown. We will add some unit-tests, which should provide confidence that this is working reliably.

I hope these tests will improve the confidence, that this solution is correct and maintainable.

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PR Comment: https://git.openjdk.org/jfx/pull/1835#issuecomment-3031120580