After locking the computer and logging back in, the stage of my JavaFX app turns black when it receives a mousevent and then stays black.
I have a dual monitor set up. When dragging the stage to the other monitor it shows correctly. Dragging it back to the first monitor it stays black there.
When the stage has been dragged over both monitors, it will turn up black on both after locking and logging back in.
This happened for all stagestyles (DECORATED, UNDECORATED and TRANSPARENT).

I found a (sort of) workaround to get it to show correctly again by adjusting the screen resolution to a different resolution and back again.