To reproduce this, run any JFXPanel app, such as the attached test program or HelloJFXPanel, on Windows with a screen scale > 1. The JFXPanel is rendered with a garbled image, suggesting that part of the code is rendering it with an incorrect scale factor.

This is a regression caused by the fix for JDK-8199592. Locally reverting that fix causes the problem to go away.

Btw, while we don't have any automated tests for this, we do have manual tests. I noticed this only when I went to run HelloJFXPanel today.

Workaround: resize the window after it is initially displayed.