Please use the attached testcase to reproduce the issue.

The test just adds a tray icon into the notification area. User has the possibility to remove the notification area from the panel on linux. Then, user may return the notification area back to the panel. These manipulations cause to loss of the tray icon. Current AWT TrayIcon implementation doesn't take care of the icons.

The behavior is questionable, someone may expect that the tray icons will not be affected by such user actions.