Simple draggable window

gistfile1.txt

using UnityEngine;
using UnityEngine.EventSystems;

public class DraggableWindow : MonoBehaviour, IBeginDragHandler, IDragHandler
{
    private float mouseOffsetY;
    private float mouseOffsetX;

    public void OnBeginDrag(PointerEventData eventData)
    {
        mouseOffsetX = transform.position.x - Input.mousePosition.x;
        mouseOffsetY = transform.position.y - Input.mousePosition.y;
    }

    public void OnDrag(PointerEventData eventData)
    {
        transform.position = new Vector3(mouseOffsetX + Input.mousePosition.x, mouseOffsetY + Input.mousePosition.y);
    }
}