src/java.desktop/share/classes/java/awt/Taskbar.java

@@ -272,10 +272,12 @@
     }
 
     /**
      * Requests user attention to the specified window.
      *
+     * The specified window must be visible in the task area.
+     *
      * @param w window
      * @throws SecurityException if a security manager exists and it denies the
      * {@code RuntimePermission("canProcessApplicationEvents")} permission.
      * @throws UnsupportedOperationException if the current platform
      * does not support the {@link Taskbar.Feature#USER_ATTENTION_WINDOW} feature

@@ -373,10 +375,12 @@
     /**
      * Affixes a small badge to this application's icon in the task area
      * for the specified window.
      * It may be disabled by system settings.
      *
+     * The specified window must be visible in the task area.
+     *
      * @param w window to update
      * @param badge image to affix to the icon
      * @throws SecurityException if a security manager exists and it denies the
      * {@code RuntimePermission("canProcessApplicationEvents")} permission.
      * @throws UnsupportedOperationException if the current platform

@@ -407,10 +411,12 @@
     }
 
     /**
      * Displays a determinate progress bar in the task area for the specified
      * window.
+     *
+     * The specified window must be visible in the task area.
      * <br>
      * The visual behavior is platform and {@link State} dependent.
      * <br>
      * This call cancels the {@link State#INDETERMINATE INDETERMINATE} state
      * of the window.

@@ -435,10 +441,12 @@
         }
     }
 
     /**
      * Sets a progress state for a specified window.
+     *
+     * The specified window must be visible in the task area.
      * <br>
      * Each state displays a progress in a platform-dependent way.
      * <br>
      * Note than switching from {@link State#INDETERMINATE INDETERMINATE} state
      * to any of determinate states may reset value set by