Check if the systray is initialized before hiding the main frame

src/net/java/sip/communicator/impl/gui/main/MainFrame.java

@@ -1920,7 +1920,8 @@ protected void windowClosing(WindowEvent event)
         // On Mac systems the application is not quited on window close, so we
         // don't need to warn the user.
         if (!GuiActivator.getUIService().getExitOnMainWindowClose()
-            && !OSUtils.IS_MAC)
+            && !OSUtils.IS_MAC
+            && GuiActivator.getSystrayService().checkInitialized())
         {
             SwingUtilities.invokeLater(new Runnable()
             {

src/net/java/sip/communicator/impl/osdependent/jdic/SystrayServiceJdicImpl.java

@@ -469,7 +469,8 @@ else if (originalDockImage != null)
         }
     }
 
-    private boolean checkInitialized()
+    @Override
+    public boolean checkInitialized()
     {
         if (!initialized)
             logger.error("Systray not init");

src/net/java/sip/communicator/service/systray/SystrayService.java

@@ -129,4 +129,10 @@ public PopupMessageHandler setActivePopupMessageHandler(
      * Selects the best available popup message handler
      */
     public void selectBestPopupMessageHandler();
+
+    /**
+     * Checks if the systray icon has been initialized.
+     * @return True if the systray is initialized, false otherwise.
+     */
+    public boolean checkInitialized();
 }