Currently, I am using JDK 15 and JavaFX 15 in GNOME/Wayland on Linux on a 4K monitor. It appears that the produced apps cannot detect my 200% upscale setting.
When researching I came up with this bug ticket that suggests moving to JavaFX 11, which is no longer working.
How should I detect and force upscale my JavaFX applications?
The ticket does not suggest downgrading to JavaFX 11. It suggest upgrading from 8. As you are already using 15 that's fine. Nevertheless I would suggest to try the latest EA release of JavaFX which is 17-ea+2 at the time of this writing, in order to see whether your problem has been fixed already. If not submit a bug report. There recently was a discussion on the mailing list about such a bug: https://mail.openjdk.java.net/pipermail/openjfx-dev/2021-February/028827.html Maybe that helps.
