C#

public ArrayList detectTilesToRedraw(Rectangle srcArea, bool bUp)
        {
            ArrayList pTileRedrawList = new ArrayList();//array to hold objects which need redrawing
            int nTop = srcArea.Y / Map_Definitions.m_nCellHeight ; //will always get the bottom positon   
            //of the sprite
            
            //scan through our map layer cells
            for (int i = 0; i < m_pObjectList.Count; ++i)
            {
                Object pObj = m_pObjectList[i];//main array reperesents each row
                if (pObj is ArrayList)
                {
                    ArrayList pList = (ArrayList)pObj;//sub array represents each column
                    for (int j = 0; j < pList.Count; ++j)
                    {
                        Tile_Object pTile = (Tile_Object)pList[j];//get tile object at row i column j
                        Object pSubObj = pTile.getObject();//get the object held in the tile
                        if (pSubObj is Graphic_Object)// is it a graphic object (sprite)
                        {
                            Graphic_Object pGraphicObject = (Graphic_Object)pSubObj;//cast to graphic 
                            //object
                            int nTileTop = pGraphicObject.getPosition().Y / Map_Definitions.m_nCellHeight;
                            //if direction of character is down (not up)
                            if (!bUp)
                            {   
                                //add all graphic objects that are at the same position or are more than  
                                //the characteers positon (grid-wise)                             
                                if (nTileTop >= nTop)
                                {
                                    pTileRedrawList.Add(pGraphicObject);
                                }
                            }
                            //else direction of character is up
                            else
                            {
                                //add all graphic objects that are at the same position or are less than  
                                //the characteers positon (grid-wise)  
                                if (nTileTop <= nTop)
                                {
                                    pTileRedrawList.Add(pGraphicObject);
                                }
                            }

                        }
                    }
                }
            }

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent(); //Requires a button
    }

    private void button1_Click(object sender, EventArgs e)
    {
        Form2 f2 = new Form2();
        //f2.Show();
        f2.ShowDialog();
    }
}

public partial class Form2 : Form
{
    public Form2()
    {
        InitializeComponent();
    }
    Form3 f3 = new Form3();
    private void Form2_Load(object sender, EventArgs e)
    {
        f3.Show();
    }
    bool isJustActivated = false;
    private void Form2_Activated(object sender, EventArgs e)
    {
        if (!isJustActivated)
        {
            isJustActivated = true;
            f3.Activate();

            bool tmp_holdValue = this.TopMost;
            this.TopMost = true; //get back the focus
            this.TopMost = tmp_holdValue;
        }
        else
            isJustActivated = false;
    }

public partial class Form3 : Form
{
    public Form3()
    {
        InitializeComponent();
        this.BackColor = Color.Green; //a green square form to identify it clearly
        this.FormBorderStyle = FormBorderStyle.None;
    }
}