Public Class Form1
    Dim WithEvents Lb As New ListBox With {.Bounds = New Rectangle(40, 30, 200, _
      200), .Parent = Me}
    Dim Pb As New PictureBox With {.Width = 40, .Height = 40, .Parent = Lb, _
    .Visible = False, .BackColor = Color.Black}
 
    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) _
      Handles MyBase.Load
        Lb.Items.AddRange({"Red", "Green", "Blue", "Yellow", "Pink", "Gold", _
        "Magenta", "Black"})
    End Sub
 
    Private Sub Lb_MouseMove(sender As Object, e As _
      System.Windows.Forms.MouseEventArgs) Handles Lb.MouseMove
        Dim itm As Int32 = Lb.IndexFromPoint(e.X, e.Y)
        If itm = -1 Then
            Pb.Visible = False
        Else
            Dim y As Int32 = e.Y
            If y > Lb.Height - 45 Then y = Lb.Height - 45
            Pb.Location = New Point(e.X + 20, y)
            Pb.BackColor = Color.FromName(Lb.Items.Item(itm).ToString)
            Pb.Visible = True
        End If
    End Sub
 
    Private Sub Lb_MouseLeave(sender As Object, e As System.EventArgs) Handles _
      Lb.MouseLeave
        Pb.Visible = False
    End Sub
End Class