Simplify handling of window hiding events

src/main/java/org/cryptomator/ui/addvaultwizard/CreateNewVaultLocationController.java

@@ -132,15 +132,7 @@ public class CreateNewVaultLocationController implements FxController {
 	@FXML
 	public void initialize() {
 		var task = backgroundExecutor.submit(this::loadLocationPresets);
-		var onHiddenAction = window.getOnHidden();
-		if(onHiddenAction != null) {
-			window.setOnHidden(evt -> {
-				task.cancel(true);
-				onHiddenAction.handle(evt);
-			});
-		} else {
-			window.setOnHidden(_ -> task.cancel(true));
-		}
+		window.addEventHandler(WindowEvent.WINDOW_HIDING, _ -> task.cancel(true));
 		locationPresetsToggler.selectedToggleProperty().addListener(this::togglePredefinedLocation);
 		usePresetPath.bind(locationPresetsToggler.selectedToggleProperty().isNotEqualTo(customRadioButton));
 	}