No repeated name allowed

src/ui/view/AddElementPopUp.java

@@ -148,8 +148,17 @@ public class AddElementPopUp extends JDialog {
 						} else {
 							// JOptionPane.showMessageDialog(new JFrame(),
 							// "Please enter a Name");
+
+							if (elementName.getText().length() == 0) {
+								JLabel errorString = new JLabel("No name");
+								errorString.setBounds(200, 8, 200, 20);
+								contentPanel.add(errorString);
+							} else if (repeated) {
+								JLabel errorString = new JLabel("Name already given");
+								errorString.setBounds(240, 8, 100, 20);
+								contentPanel.add(errorString);
+							}
 							elementName.setBackground(new Color(255, 50, 50));
-							// Jlabel repeatedString = new JLabel();
 						}
 					}
 				});