For those who have the same problem, I would like to share the solution I adopted:
Since my monitor has the fixed resolution at 1366x768, I have locked the /boot/config.txt (raspbian distro) file at this resolution and changed the variable framebuffer to 1350x750, so the mouse does not disappear from the screen and the problem is solved. Not the best solution, but it was the most practical I could get.
Apparently this is a java + raspberry problem and not a B4J problem.
Marcelo