src/main/java/de/hitec/nhplus/controller/MainWindowController.java

@@ -12,6 +12,10 @@ public class MainWindowController {
 
     @FXML
     private BorderPane mainBorderPane;
+    @FXML
+    public void initialize() {
+        handleShowAllPatient(null);
+    }
 
     @FXML
     private void handleShowAllPatient(ActionEvent event) {