Fixed suppressed "invalid mountpoint" messages

Fixed #1515

main/ui/src/main/java/org/cryptomator/ui/unlock/UnlockWorkflow.java

@@ -204,6 +204,7 @@ public class UnlockWorkflow extends Task<Boolean> {
 	private void showInvalidMountPointScene() {
 		Platform.runLater(() -> {
 			window.setScene(invalidMountPointScene.get());
+			window.show();
 		});
 	}