diff --git a/src/main/java/fr/insa/clavardator/ui/chat/ChatHeaderController.java b/src/main/java/fr/insa/clavardator/ui/chat/ChatHeaderController.java
index 084a68d..c613412 100644
--- a/src/main/java/fr/insa/clavardator/ui/chat/ChatHeaderController.java
+++ b/src/main/java/fr/insa/clavardator/ui/chat/ChatHeaderController.java
@@ -2,10 +2,12 @@ package fr.insa.clavardator.ui.chat;
 
 import fr.insa.clavardator.ui.users.UserActiveIndicatorController;
 import fr.insa.clavardator.users.PeerUser;
+import javafx.application.Platform;
 import javafx.fxml.FXML;
 import javafx.fxml.Initializable;
 import javafx.scene.control.Label;
 
+import java.beans.PropertyChangeEvent;
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.ResourceBundle;
@@ -16,12 +18,26 @@ public class ChatHeaderController implements Initializable {
 	private Label remoteUsernameLabel;
 	@FXML
 	private UserActiveIndicatorController indicatorController;
+	private PeerUser user;
 
 	@Override
 	public void initialize(URL location, ResourceBundle resources) {
 	}
 
+	private void onUsernameChange(PropertyChangeEvent propertyChangeEvent) {
+		if (propertyChangeEvent.getPropertyName().equals("username")) {
+			final String newUsername = (String) propertyChangeEvent.getNewValue();
+			Platform.runLater(() -> remoteUsernameLabel.setText(newUsername));
+		}
+	}
+
 	public void setRemoteUser(PeerUser remoteUser) {
+		if (this.user != null) {
+			// remove old observer before setting new user
+			this.user.removeObserver(this::onUsernameChange);
+		}
+		this.user = remoteUser;
+		user.addObserver(this::onUsernameChange);
 		remoteUsernameLabel.setText(remoteUser.getUsername());
 		indicatorController.setUser(remoteUser);
 		indicatorController.setSize(10.0);
diff --git a/src/main/java/fr/insa/clavardator/ui/users/UserActiveIndicatorController.java b/src/main/java/fr/insa/clavardator/ui/users/UserActiveIndicatorController.java
index 6ce832a..bdcf042 100644
--- a/src/main/java/fr/insa/clavardator/ui/users/UserActiveIndicatorController.java
+++ b/src/main/java/fr/insa/clavardator/ui/users/UserActiveIndicatorController.java
@@ -2,6 +2,7 @@ package fr.insa.clavardator.ui.users;
 
 import fr.insa.clavardator.users.PeerUser;
 import fr.insa.clavardator.util.Log;
+import javafx.application.Platform;
 import javafx.fxml.FXML;
 import javafx.fxml.Initializable;
 import javafx.scene.shape.Circle;
@@ -34,7 +35,7 @@ public class UserActiveIndicatorController implements Initializable {
 		if (propertyChangeEvent.getPropertyName().equals("state")) {
 			final PeerUser.State newState = (PeerUser.State) propertyChangeEvent.getNewValue();
 			Log.v(this.getClass().getSimpleName(), "User state updated to " + newState.toString());
-			updateState(newState == PeerUser.State.CONNECTED);
+			Platform.runLater(() -> updateState(newState == PeerUser.State.CONNECTED));
 		}
 	}