Using DialogFX lib directly or w/i JFXtras, designate same button as default & cancel (example use case: prompting user to delete something, want to default in all cases to "No" button). Calls to setDefaultButton() & setCancelButton() work, code executes fine on Mac (ENTER & ESCAPE both return value for designated button), but not on Windows. Tested on at least two Windows machines with same results.

Some sample code to setup dialog is:

        List<String> buttonLabels = new ArrayList<>(2);
        buttonLabels.add("Affirmative");
        buttonLabels.add("Negative");
        
        DialogFX dialog = new DialogFX(Type.QUESTION);
        dialog.setTitleText("Question Dialog Box Example");
        dialog.setMessage("This is an example of an QUESTION dialog box, created using DialogFX. This also demonstrates the automatic wrapping of text in DialogFX. Would you like to continue?");
        dialog.addButtons(buttonLabels, 1, 1);
        int i = dialog.showDialog();
        System.out.println("Return code=" + i);

DialogFX.java attached, also available via GitHub.