Various overrides to control or disable UI and rendering scaling on Windows were added as safeguards when the Windows HiDPI support was added to JavaFX under RT-27960. Those controls are sometimes invoked by parts of the system when interacting with modules that don't fully support UI scaling (JFXPanel and SwingNode for instance).

Unfortunately, the font used to scale according to the Windows DPI settings even when we weren't scaling the rest of the UI and when the controls are used to disable our general UI scaling, it leaves us in a situation where we down-scale the fonts as well. This may or may not be a bad thing since when the fonts are scaled up according to the screen DPI and the rest of the application is not also scaled, layout problems can occur.

This issue is filed to track the problem so that we can document any issues or concerns that may arise due to this new behavior for the system font size. The final answer may well be "this is working as intended", but we lack data to know what the right thing to do is...