this.NotifyIcon.BalloonTipShown not executing

[C# Programming]

I'm trying to build a pop-up graph in c# using this.NotifyIcon.BalloonTipShown but it doesn't execute in Windows 7 . Is there any alternative way to open a form when the user hovers the mouse over the icon and close the form when the mouse is moved away ?

Im using the code below

//
// NotifyIcon
//
this.NotifyIcon.BalloonTipIcon = System.Windows.Forms.ToolTipIcon.Info;
this.NotifyIcon.BalloonTipText = "RapidNAS Warez Made Easy ...";
this.NotifyIcon.BalloonTipTitle = "RapidNAS";
this.NotifyIcon.Icon = ((System.Drawing.Icon)(resources.GetObject("NotifyIcon.Icon")));
this.NotifyIcon.Text = "RapidNAS Warez Made Easy ...";
this.NotifyIcon.Visible = true;
this.NotifyIcon.BalloonTipClosed += new System.EventHandler(this.HideGraph);
this.NotifyIcon.BalloonTipShown += new System.EventHandler(this.ShowGraph);

private void LaunchDownloadStatus(object sender, MouseEventArgs e)
{
Popup form = new Popup();
form.Show();
}

private void HideGraph(object sender, EventArgs e)
{

}