Properly override updateItem method of list cells

src/main/java/envoy/client/ui/ContactListCell.java

@@ -28,7 +28,10 @@ public class ContactListCell extends ListCell<Contact> {
 	@Override
 	protected void updateItem(Contact contact, boolean empty) {
 		super.updateItem(contact, empty);
-		if (!empty && contact != null) {
+		if (empty || contact == null) {
+			setText(null);
+			setGraphic(null);
+		} else {
 			// the infoLabel displays specific contact info, i.e. status of a user or amount
 			// of members in a group
 			Label infoLabel = null;
@@ -51,7 +54,7 @@ public class ContactListCell extends ListCell<Contact> {
 						break;
 				}
 				infoLabel.setTextFill(textColor);
-			} else 
+			} else
 				// group specific infos
 				infoLabel = new Label(String.valueOf(((Group) contact).getContacts().size()) + " members");
 			setGraphic(new VBox(new Label(contact.getName()), infoLabel));

src/main/java/envoy/client/ui/MessageListCell.java

@@ -45,10 +45,15 @@ public class MessageListCell extends ListCell<Message> {
 	@Override
 	protected void updateItem(Message message, boolean empty) {
 		super.updateItem(message, empty);
-		setGraphic(!empty && message != null ? new HBox(
+		if(empty || message == null) {
+			setText(null);
+			setGraphic(null);
+		} else {
+			setGraphic(new HBox(
 					new VBox(
 					 new Label(dateFormat.format(message.getCreationDate())),
 					 new Label(message.getText())),
-					new Label("", new ImageView(statusImages.get(message.getStatus())))) : null);
+					new Label("", new ImageView(statusImages.get(message.getStatus())))));
+		}
 	}
 }