Jpopupmenu Bug/Glitch When Showing Submenu

[Davide Perini]

Hi all,
I'm using a JPopupMenu to workaround the lack of a "real tray icon" in 
JavaFX.

This is the simple code I'm using:
https://github.com/Sylvain-Bugat/tray-icon-skeleton/blob/master/src/main/java/com/github/sbugat/trayiconskeleton/TrayIconMainClass.java

It all works well until I add a submenu (JMenu) to my JPopupMenu.

This is how the tray looks when no glitch appear:


and this is the tray how looks like when the glitch of the submenu appers:




to trigger the glitch I can simply move the mouse over the submenu and 
then move the mouse over the other jmenuitem.

Any idea on why I have this error?

Thanks
Davide