diff --git a/src/org/hwo/ui/JObjectSelector.java b/src/org/hwo/ui/JObjectSelector.java
index 95ee05c..a06dcec 100644
--- a/src/org/hwo/ui/JObjectSelector.java
+++ b/src/org/hwo/ui/JObjectSelector.java
@@ -30,6 +30,7 @@ public class JObjectSelector extends JDialog {
 		JObjectSelector os = new JObjectSelector();
 		os.setItems(items);
 		os.setVisible(true);
+		os.dispose();
 		return os.selectedItem;
 	}
 	
diff --git a/src/org/hwo/ui/dialog/SerialPortChooser.java b/src/org/hwo/ui/dialog/SerialPortChooser.java
index e3a79b7..24e4b2a 100644
--- a/src/org/hwo/ui/dialog/SerialPortChooser.java
+++ b/src/org/hwo/ui/dialog/SerialPortChooser.java
@@ -128,8 +128,11 @@ public class SerialPortChooser extends JDialog {
 	
 	private void accept()
 	{
-		selectedSerialPort = new NewSerialPort(cbPortList.getSelectedItem().toString());
-		setVisible(false);
+		String portName = (String)cbPortList.getSelectedItem();
+		if (portName != null){
+			selectedSerialPort = new NewSerialPort(portName);
+			setVisible(false);
+		}
 	}
 	
 	private void cancel()