Hi Martin,
Just to say thanks for looking into it and the following explanation, it's
good to know. There's some quirks to be aware of for sure.
Kind Regards,
Cormac
On Mon, 7 Jul 2025 at 15:50, Martin Fox <martinfox...@gmail.com> wrote:
> Cormac,
>
> When you call Dialog.show everything happens in the order you expect. When
> you call Dialog.showAndWait the order of operations changes. For one, the
> Dialog code issues the DIALOG_SHOWN event *before* showing the window (it
> wants to send out that event before an internal call to Window.showAndWait
> blocks). For two, when Window.sizeToScene is called on a window that’s not
> yet visible it gets deferred. The end result is that with
> Dialog.showAndWait your onShown handler gets called before the window is
> sized to the scene but when you use Dialog.show your onShown handler is
> called after.
>
> I don’t think any of this is documented. I've run into the deferred
> sizeToScene behavior before. I didn’t dig much but it looks like it was
> added over a decade ago in response to some bug reports. The timing of
> Dialog.setOnShown is also old behavior. There’s a comment in the
> Dialog.java about this:
>
> // this is slightly odd - we fire the SHOWN event before the show()
> // call, so that users get the event before the dialog blocks
>
>
> So I can see what’s going on in case #2. Due to the re-ordering the
> sizeToScene logic is happening after the window’s minimum size is set. The
> docs don’t say what should happen if the scene’s desired size is less than
> the window’s minimum. What you’re getting is a scene that doesn’t fill the
> window. One work-around for case 2 is to call setOnShown on the dialog’s
> window instead of the dialog itself.
>
> BTW, I think what you’re seeing in case #3 is correct and not a bug.
> You’re altering the size of the scene after the window has been sized and
> shown. I wouldn’t expect the window to automatically re-size to match the
> new scene dimensions. I think the expectation is that you would alter the
> scene’s dimensions in onShowing instead of onShown.
>
> Martin
>
> On Jul 3, 2025, at 2:24 PM, Cormac Redmond <credm...@certak.com> wrote:
>
> Hi,
>
> I have noticed inconsistent and confusing size/layout behaviour with
> Dialogs when changing min width or height (after shown).
>
> The behaviour depends on whether changing min width/height on the Stage,
> or the DialogPane itself, and whether show() or showAndWait() is used.
>
> In summary:
>
> 1. Set Stage mins + show()
> - no bug
> 2. Set Stage mins + showAndWait()
> - improper layout: background applies only to label (i.e., size
> before re-size), button wrong position, re-sizing window fixes the
> problem
> 3. 3 Set DialogPane mins + show()
> - min sizes are ignored, button is visible, until it comes into
> focus, and then the button disappears, you can find it if you resize
> window
> close to the mins set
> 4. 4 Set DialogPane mins + showAndWait()
> - no bug
>
> It's happening in JFX23/24/25. Note, these may seem trivial/fixable, or
> you may ask "why would you do that?", but there are reasons I won't clutter
> the mail with.
>
> Anyway, it's best presented with a set of examples and code.
>
> Re points 1 and 2 above, exact same code, except red is showAndWait() and
> green is show():
>
> <image.png>
>
> Obviously, they should behave the same. Then slightly resize the red one:
>
> <image.png>
>
>
> Examples 3 and 4 above -- again, same code. Purple is show(), yellow is
> showAndWait().
>
> <image.png>
>
> After you close the yellow dialog:
>
> <image.png>
>
> They should be the same size from the outset.
>
>
>
> public class DialogBug extends Dialog<Boolean> {
>
> public DialogBug(final String s, boolean flip) {
> setTitle("Bug");
> setResizable(true);
>
> final DialogPane dp = getDialogPane();
> dp.setStyle(s);
> dp.getButtonTypes().add(ButtonType.CLOSE);
> dp.setContent(new Label("Content"));
>
> // Setting stage size causes the bug
> setOnShown(e -> {
>
> if (flip) {
> // Set stage sizes
> Stage st = (Stage) dp.getScene().getWindow();
> st.setMinHeight(260);
> st.setMinWidth(360);
> } else {
> // Set dialog sizes: note buttons disappear when you resize
> dp.setMinHeight(260);
> dp.setMinWidth(360);
> }
> });
> }
>
> public static class BugApp extends Application {
> @Override
> public void start(final Stage st) throws Exception {
>
> final boolean FLIP_ME = true; // make true for other bug
>
> if (FLIP_ME) {
> // Note: bug doesn't happen when using show() only. Stage
> is fully green on show.
> new DialogBug("-fx-background-color: green;",
> true).show(); // NO BUG
>
> // showAndWait presents the bug; background not fully
> drawn, button shifts on re-size
> new DialogBug("-fx-background-color: red;",
> true).showAndWait(); // BUG
> } else {
> // A different type of issue: two different sizes and
> button behaviour
> // Notice:
> // - same dialogs, different sizes
> // - how button in purple dialog shifts when yellow dialog
> pane is closed
> new DialogBug("-fx-background-color: purple;",
> false).show(); // BUG
>
> new DialogBug("-fx-background-color: yellow;",
> false).showAndWait(); // NO BUG
> }
> }
> }
> }
>
> Thoughts?
>
>
>
> Kind Regards,
> Cormac
>
>
>
