Public Class Form1
 
    'Eckdaten des NotifyIcons
    Private NotifyIcon_Left As Integer
    Private NotifyIcon_Right As Integer
    Private NotifyIcon_Bottom As Integer
    Private NotifyIcon_Top As Integer
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        NotifyIcon_Left = 30000                     'Sollte nur außerhalb der 
        ' möglichen Auflösung sein
        NotifyIcon_Bottom = 0
        NotifyIcon_Right = 0
        NotifyIcon_Top = 30000                      'Sollte nur außerhalb der 
        ' möglichen Auflösung sein
        NotifyIcon1.Icon = New System.Drawing.Icon("C:\Icon1.ico")
        NotifyIcon1.Text = "MouseOver"
        NotifyIcon1.Visible = True
        Timer1.Enabled = True
    End Sub
 
    Private Sub NotifyIcon_CreateMouseOver(ByVal x As Integer, ByVal y As _
      Integer)
        'Die Position des Icons einlesen
 
        'Beim ersten Durchlauf
        If x < NotifyIcon_Left Then
            NotifyIcon_Left = x
            'Falls das Icon durch andere nach links verschoben wird
        ElseIf x < NotifyIcon_Left And NotifyIcon_Left - 17 > x Then
            NotifyIcon_Left = x
            'Falls das Icon durch andere nach rechts verschoben wird
        ElseIf x > NotifyIcon_Left And NotifyIcon_Left + 17 < x Then
            NotifyIcon_Left = x
        End If
 
        If x > NotifyIcon_Right Then
            NotifyIcon_Right = x
        ElseIf x > NotifyIcon_Right And NotifyIcon_Right + 17 < x Then
            NotifyIcon_Right = x
        ElseIf x < NotifyIcon_Right And NotifyIcon_Right - 17 > x Then
            NotifyIcon_Right = x
        End If
 
        'Hier kann nichts verschoben werden
        If y <= NotifyIcon_Top Then NotifyIcon_Top = y
        If y >= NotifyIcon_Bottom Then NotifyIcon_Bottom = y
    End Sub
 
    Private Function NotifyIcon_MouseOver(ByVal x As Integer, ByVal y As _
      Integer) As Boolean
        'Abfragen ob die Maus beim MouseMove im IconBereich ist
        If x > NotifyIcon_Left And x < NotifyIcon_Right And _
           y < NotifyIcon_Bottom And y > NotifyIcon_Top Then
            NotifyIcon_MouseOver = True
        Else
            NotifyIcon_MouseOver = False
        End If
    End Function
 
    Private Sub NotifyIcon1_MouseMove(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles NotifyIcon1.MouseMove
        'Die Aktuelle Mausposition an CreateMouseOver senden
        NotifyIcon_CreateMouseOver(Cursor.Position.X, Cursor.Position.Y)
    End Sub
 
    Private Sub NotifyIcon1_MouseClick(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles NotifyIcon1.MouseClick
        'Beinem Mausklick, soll das Fenster sichtbar bleiben
        Form2.Show()
        'dazu den Timer abschalten (wird beim beenden von Form2 wieder 
        ' eingeschaltet)
        Timer1.Enabled = False
    End Sub
 
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Timer1.Tick
        'Solange der Timer läuft, wird das Fenster beim MouseOver angezeigt
        If NotifyIcon_MouseOver(Cursor.Position.X, Cursor.Position.Y) = True _
          Then
            Form2.Show()
        Else
            Form2.Hide()
        End If
    End Sub
End Class

Public Class Form2
    'Damit andere Anwendungen, die evtl. den Fokus haben müssen
    'nicht gestört werden, das Fenster ohne Fokus anzeigen
    Protected Overrides ReadOnly Property ShowWithoutActivation() As Boolean
        Get
            Return True
        End Get
    End Property
 
    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Me.Height = 150
        Me.Width = 250
        'Das Fenster nicht in der Taskbar anzeigen
        Me.ShowInTaskbar = False
        'Und Unten Rechts über der Taskleiste anzeigen
        Me.Top = My.Computer.Screen.WorkingArea.Height - Me.Height
        Me.Left = My.Computer.Screen.WorkingArea.Width - Me.Width
    End Sub
 
    Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        'Den Timer wieder einschalten, damit NotifyIconMouseOver wieder klappt
        Form1.Timer1.Enabled = True
    End Sub
 
End Class