public CustomDropDown()
{
Popup = GetPopup();
items = new List <Item>();
tween = new Tween();
AddChild(tween);
cachedPopupHSeparation = Popup.GetConstant("hseparation");
cachedPopupVSeparation = Popup.GetConstant("vseparation");
var checkSize = Popup.GetIcon("checked").GetSize();
// Set the custom icon size
iconSize = new Vector2(checkSize.x - 2, checkSize.y - 2);
Popup.RectClipContent = true;
Connect("about_to_show", this, nameof(OnPopupAboutToShow));
Popup.Connect("draw", this, nameof(RedrawPopup));
}