RFR: 8351867: No UI changes while iconified

[John Hendrikx]

On Tue, 18 Mar 2025 15:01:46 GMT, Ambarish Rapte <arapte at openjdk.org> wrote:

> This does fix the issue on windows. The issue on mac seems intermittent even without this change, and stays intermittent with this change.
> 
> The change seems to achieve the intended but the trigger check may not be the best way. `updateSceneState` is used when there are any changes with scene properties. The redraw should be triggered by checking the change in scene graph. This change just triggers irrespective of that.

I think the bug can also appear without the scene graph having changed, when you iconify immediately programmatically (ie. before showing the window).  The change detection would need to make sure it also detects the case where a scene was not drawn yet at all:


public class App extends Application {

    public static void main(String[] args) {
        Application.launch(args);
    }

    @Override
    public void start(Stage stage) {
        Scene scene = new Scene(new Label("This should be modified when the signal is received"), 500, 500);

        stage.setScene(scene);

        stage.setIconified(true);
        stage.show();
    }
}

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PR Comment: https://git.openjdk.org/jfx/pull/1733#issuecomment-2734965738