The problem appears when I run any Java application with tray icon (for example, reg test java/awt/TrayIconTest).

Just press the displayMessage button, the balloon will be shown. The balloon contans an icon if the message type is specified. Close the balloon (just press by mouse on it). Press on the displayMessage button again, a balloon will be shown but the balloon doesn't contain an icon even if the message type is specified.

This is reproducible on jdk7 b19, linux.