ComboBox item height bug

[Cormac Redmond]

Hi,

I have found a height bug when I am trying to reduce the height of one
ComboBox item (a Separator) in a simple ComboBox.

One would expect that to achieve this, you'd set the maximum height for
that particular ListCell; but this has no effect.

Instead what I need to do is set the *minimum* height (but to the value I
wish to be the maximum height), and I must *also *set the *maximum *height
to any value (if I do not, my minimum height (i.e., my desired maximum)
gets ignored)...

For example, if I want the maximum height of this Separator to be 6, I must
set the minimum height to 6 and I must set the maximum height to anything,
even 1.

Obviously this is counter-intuitive and doesn't make any logical sense.

Example to reproduce (running from JFX master branch):

public class ComboBoxHeightBug extends Application {
    public static void main(String[] args) {
        launch(args);
    }

    public void start(Stage stage) {
        ComboBox<Object> cb = new ComboBox<>();
        cb.getItems().addAll("Apple", "Banana",  new Separator() ,
"Carrot", "Lettuce");
        cb.setCellFactory(_ -> new ListCell<>() {
            protected void updateItem(Object item, boolean empty) {
                super.updateItem(item, empty);
                if (empty || item == null) {
                    setText(null);
                    setGraphic(null);
                    setStyle("");
                    // Set back to default
                    setMinHeight(USE_PREF_SIZE);
                    setMaxHeight(Double.MAX_VALUE);
                } else if (item instanceof Separator) {
                    setText(null);
                    setGraphic((Separator) item);
                    setDisable(true);
                    setMinHeight(6); // This is required for any "max
height" to apply, and appears to be the value that is used to determine
height
                    setMaxHeight(1); // Setting this (to 6) should work on
its own, it doesn't, the value appears irrelevant -- but it MUST be set to
get the separator height to be 6
                } else {
                    setText(item.toString());
                    setGraphic(null);
                    setStyle("");
                    // Set back to default
                    setMinHeight(USE_PREF_SIZE);
                    setMaxHeight(Double.MAX_VALUE);
                }
            }
        });

        cb.getSelectionModel().selectFirst();
        stage.setScene(new Scene(cb, 200, 100));
        stage.show();
    }
}

Note: I have noticed a few issues like this in general, whereby it requires
trial and error to get *some* desired height to apply; without any apparent
logic as to how these values are being arrived at or how they're triggered
to be used (I have logged bugs before on this)...


Kind Regards,
Cormac
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