Resize / Move borderless form

Public Partial Class Form1
    Inherits Form

    Public Sub New()
        InitializeComponent()
        Me.FormBorderStyle = FormBorderStyle.None
        Me.DoubleBuffered = True
        Me.SetStyle(ControlStyles.ResizeRedraw, True)
    End Sub

    Private Const cGrip As Integer = 16
    Private Const cCaption As Integer = 32

    Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
        Dim rc As Rectangle = New Rectangle(Me.ClientSize.Width - cGrip, Me.ClientSize.Height - cGrip, cGrip, cGrip)
        ControlPaint.DrawSizeGrip(e.Graphics, Me.BackColor, rc)
        rc = New Rectangle(0, 0, Me.ClientSize.Width, cCaption)
        e.Graphics.FillRectangle(Brushes.DarkBlue, rc)
    End Sub

    Protected Overrides Sub WndProc(ByRef m As Message)
        If m.Msg = &H84 Then
            Dim pos As Point = New Point(m.LParam.ToInt32())
            pos = Me.PointToClient(pos)

            If pos.Y < cCaption Then
                m.Result = CType(2, IntPtr)
                Return
            End If

            If pos.X >= Me.ClientSize.Width - cGrip AndAlso pos.Y >= Me.ClientSize.Height - cGrip Then
                m.Result = CType(17, IntPtr)
                Return
            End If
        End If

        MyBase.WndProc(m)
    End Sub
End Class