//private RectTransform _rectTransform;
public void SetupSize(int itemCount, UIMenuItem prefab)
{
_layoutGroup = GetComponent <VerticalLayoutGroup>();
float itemSize = prefab.GetComponent <RectTransform>().rect.height;
float contentHeight = itemCount * (itemSize + _layoutGroup.spacing) + _layoutGroup.padding.top +
_layoutGroup.padding.bottom;
Vector2 size = GetComponent <RectTransform>().sizeDelta;
size.y = contentHeight;
GetComponent <RectTransform>().sizeDelta = size;
}