Sounds like the same bug I've already reported to the OpenJFX project: https://bugs.openjdk.java.net/browse/JDK-8236689 <https://bugs.openjdk.java.net/browse/JDK-8236689> It occurred for me the first time after updating to macOS 10.15 / Catalina and only on non-retina displays.
Unfortunately there was no progress on this bug yet. Bye, Stefan
