Hi Pavel, you're probably talking about the Linux implementation, because both on macOS and Windows, extended stages already have a window border.
In general, an extended stage is like a decorated stage where the OS is responsible for drawing window borders. It is neither intended nor supported that applications draw their own window borders. So instead of adding new API, would your use case be covered if extended stages on Linux just looked like platform-native decorated windows? On Fri, Jun 19, 2026 at 4:23 PM PavelTurk <[email protected]> wrote: > > In addition to JDK-8386317, I proposed adding an API that would allow > JavaFX applications to obtain the window corner radius from the > operating system. However, Michael Strauß pointed out that this is most > likely not feasible because operating systems generally do not expose > such information. > > Let's look at the problem from a practical perspective. Virtually every > application running in a non-maximized window requires a border > (typically 1 px). This is a standard UI convention. If JavaFX supports > EXTENDED windows with rounded corners, the corners of that border must > also be rendered correctly. Otherwise, the result will look visually > inconsistent. > > If obtaining the corner radius from the OS is not possible, I would > suggest one of the following solutions: > > 1. Add an API that allows the operating system to render the window > border itself, while the JavaFX developer only specifies its > appearance (color, thickness, dash pattern, etc.). > 2. Allow the JavaFX developer to specify the corner radius explicitly, > while the operating system uses that information solely for > rendering the native window shadow. > > Best regards, Pavel >
