protected Control(int x, int y, int width, int height)
{
area = new Rect(x, y, width, height);
children = new ControlCollection(this);
//X = x;
//Y = y;
//Width = width;
//Height = height;
}
internal Enumerator(ControlCollection collection)
{
_collection = collection;
_index = -1; // not started.
_version = _collection.version;
_currentElement = null;
}