Hi Andy,
Thank you for your reply.
That sounds good, re: a menu item factory. E.g., give the devs full control.
I think the ability to disable it (or have it disabled by default) would be
good too: a dev might not *care* about supporting the menu items in many
cases. E.g., if a TabPane only has three (graphic-based) tabs, and the user
decides to resize the window to something unusually small, then who cares
if they can't traverse the tabs, at that size? Nobody realistically expects
to be able in such a scenario anyway, and it's better to have no menu than
a buggy one.
I don't like the fact that, today, TabPane's menu can misbehave and nobody
would know it's going to happen really. I think TabPane should throw an
exception (or log a warning) when it receives nodes it knows it will not be
able to use in the menu; especially given the menu is always-on.
I think a good overall solution would be:
1. a menu factory
2. make the menu optional for those who don't care
3. log warnings when a tab's header node will not be displayable in a
menu (i.e., if the dev hasn't provided a factory and the default "menu
factory" knowingly cannot handle it)
1. Not really sure how JFX folks feel about logging warnings, I note
it's minimal today in general, and probably for good reason
(e.g., where do
you draw the line in the sand about what should be logged vs. not)
Anyway, I think the above will be achievable without any breaking /
functionality changes...?
Kind Regards,
Cormac
On Mon, 7 Apr 2025 at 17:59, Andy Goryachev <andy.goryac...@oracle.com>
wrote:
> All very good points, thank you for this writeup!
>
>
>
> This discussion relates to https://bugs.openjdk.org/browse/JDK-8353599 .
> I've been thinking how to handle this issue, and I am leaning to agree with
> the suggestion proposed in the ticket (some sort of menu item factory).
>
>
>
> The current "hacky" solution not obviously fails, but also not scalable -
> I can see developers wanting to place a Canvas, a Path, a Pane, or any
> other kind of Node and it would be nearly impossible to "clone" these in a
> maintainable manner. With a menu item factory, however, the effort will be
> shifted on the application dev with a very simple solution.
>
>
>
> The other solution that does not involve a new API would be to limit the
> overflow menu to only list the tabs that are hidden - in this case the
> graphics Nodes can be reused by the menu items. The problem with that
> approach is the overflow menu logic becomes more complicated, to handle the
> case when menus are hidden on both ends.
>
>
>
> What do you think?
>
>
>
> -andy
>
>
>
>
>
> *From: *openjfx-dev <openjfx-dev-r...@openjdk.org> on behalf of Cormac
> Redmond <credm...@certak.com>
> *Date: *Friday, April 4, 2025 at 17:00
> *To: *openjfx-dev@openjdk.org <openjfx-dev@openjdk.org>
> *Subject: *TabPane overflow menu showing blanks
>
> Hi,
>
>
>
> TabPane tabs allow you to set graphic nodes as the header and there
> appears to be no documented limitations or best-practises on this.
>
>
>
> You might assume it's perfectly reasonable to not set a Tab's text value,
> and instead set the header as a HBox, consisting of a graphic node (left)
> and a Label (itself with a text + a graphic, right), to achieve an
> icon-text-icon style header, which is not an uncommon.
>
>
>
> However, the overflow menu, when it kicks in, will not display any text or
> graphics at all (just a blank space), if your Tab has no "text" set, and
> the header graphic is not a Label or an ImageView.
>
>
>
> It's down to this self-confessed hacky code (
> https://github.com/openjdk/jfx/blob/f31d00d8f7e601c3bb28a9975dd029390ec92173/modules/javafx.controls/src/main/java/javafx/scene/control/skin/TabPaneSkin.java#L479
> ):
>
>
>
> /**
> * VERY HACKY - this lets us 'duplicate' Label and ImageView nodes to
> be used in a
> * Tab and the tabs menu at the same time.
> */
> private static Node clone(Node n) {
> if (n == null) {
> return null;
> }
> if (n instanceof ImageView) {
> ImageView iv = (ImageView) n;
> ImageView imageview = new ImageView();
> imageview.imageProperty().bind(iv.imageProperty());
> return imageview;
> }
> if (n instanceof Label) {
> Label l = (Label)n;
> Label label = new Label(l.getText(), clone(l.getGraphic()));
> label.textProperty().bind(l.textProperty());
> return label;
> }
> return null;
> }
>
>
>
>
>
> It is not obvious at all that this is what's going to happen, or why. And
> it seems impossible to control or influence this in any reasonable way,
> without replacing the whole TabPaneSkin.
>
>
>
> Given TabPane is one of the most important and widely used controls there
> is, there could/should be some of the following:
>
> - Proper documentation on this limitation / behaviour
> - Some way to set fallback text that can be used in the menu (i.e.,
> that isn't the Tab's header's text, because one might intentionally avoid
> setting that given there's no way to hide it from the tab header)
> - Or, better yet, some way to allow you to specify tab header text
> without displaying it in the actual tab header, which could then be used by
> the hacky method as normal
> - Some way to set a callback so the developer can decide what gets
> displayed for the overflow menu
> - Some way to override the skin without needing a full copy + paste +
> rename
> - Some way to allow the dev to disable the overflow menu, if it's
> going to produce something unusable. E.g., prefer no menu than a buggy
> one...
>
>
>
> I would view this as a bug, even though it's probably been like this
> forever.
>
>
>
>
>
> Some sample code to demonstrate; just look at the menu:
>
>
> public class TabPaneMenu extends Application {
> @Override
> public void start(Stage primaryStage) {
> TabPane tabPane = new TabPane();
>
> for (int i = 1; i <= 30; i++) {
> Tab tab;
> if (i == 2) {
> tab = new Tab();
> final Label label = new Label("HBox Tab " + i);
> final HBox hBox = new HBox(label); // Will show as blank
> in overflow menu!
> tab.setGraphic(hBox);
> } else if (i == 5) {
> tab = new Tab();
> tab.setGraphic(new Label("Label Tab " + i)); // Will show
> in overflow menu, because it's a Label
> } else {
> tab = new Tab("Normal Tab " + i);
> }
>
> tab.setContent(new StackPane(new Label("This is Tab " + i)));
> tab.setClosable(false);
> tabPane.getTabs().add(tab);
>
> }
>
> Scene scene = new Scene(tabPane, 800, 600);
> primaryStage.setScene(scene);
> primaryStage.show();
> }
>
> public static void main(String[] args) {
> launch(args);
> }
> }
>
>
>
>
> Kind Regards,
>
>
>
> *Cormac Redmond*
>
> Software Engineer, Certak Ltd.
>
>
>
> e: credm...@certak.com | m: +353 (0) 86 268 2152 | w: www.certak.com
>
>
>
>
>
