Now shows success message after up-/download.

CubeControl/Frame.java

 	}
 
 	/**
+	 *	Show a dialog message to the user via this Frame.
+	 * @param title Title of message box
+	 * @param msg Error message.
+	 */
+	public void showDialog(String title, String msg) {
+		String[] Optionen = { "OK" };
+		JOptionPane.showOptionDialog(this, msg, title, JOptionPane.YES_OPTION,
+			JOptionPane.INFORMATION_MESSAGE , null, Optionen, Optionen[0]);
+	}
+
+	/**
 	 * Show an error message to the user via the most recent Frame.
 	 * @param s Error Message
 	 */
 			public void actionPerformed(ActionEvent evt) {
 				// Error messages are generated by worker
 				if (worker.cubeProbeConnected((String) serialPortSelector.getSelectedItem())) {
-					worker.cubeSendState((String) serialPortSelector.getSelectedItem());
+					if (worker.cubeSendState((String) serialPortSelector.getSelectedItem()) == -1) {
+						showDialog("Success!", "Data was sent successfuly!");
+					}
 				}
 			}
 		});
 			public void actionPerformed(ActionEvent evt) {
 				// Error messages are generated by worker
 				if (worker.cubeProbeConnected((String) serialPortSelector.getSelectedItem())) {
-					worker.cubeGetState((String) serialPortSelector.getSelectedItem());
+					if (worker.cubeGetState((String) serialPortSelector.getSelectedItem()) == -1) {
+						showDialog("Success!", "Got data successfuly!");
+					}
 				}
 			}
 		});