I wanna the buttons B and D will be remained on their places when the A and C will be disappeared, but instead of it there are shifted to the center. How could I shift them back to their places?

```
     fifty.setOnAction(e->{
            fifty.setDisable(false);
            int counter = 2;
            ArrayList<String> variants = new ArrayList<>(Arrays.asList("a","b","c","d"));
            variants.remove(trueAnswerIndex);
            String variant;
            int n = 2;

            while(counter>0){
                variant = variants.get(randInt(0,n));
                switch(variant){
                    case "a":
                        gridButtons.getChildren().remove(a);
                        variants.remove("a");
                        break;
                    case "b":
                        gridButtons.getChildren().remove(b);
                        variants.remove("b");
                        break;
                    case "c":
                        gridButtons.getChildren().remove(c);
                        variants.remove("c");
                        break;
                    case "d":
                        gridButtons.getChildren().remove(d);
                        variants.remove("d");
                        break;
                }
                counter--;
                n--;
            }
        });

```

<https://i.stack.imgur.com/pPpC4.jpg>