Custom ComboBox with editable text possible?

[Wardo]

Hello, i've been trying to customize the .Net combox and have a good result for DropDownList style of combobox, but i want to be able to write the input of the combobox as in DropDown style. As soon as i change the style, the textbox area stops responding to my OnPaint event.
Is it an impediment from Windows or is there a workaround to have a customized and editable combobox?

This would be my constructor

Public Sub New()

        InitializeComponent()

        Me.SetStyle(ControlStyles.UserPaint _
                Or ControlStyles.AllPaintingInWmPaint _
                Or ControlStyles.Opaque _
                Or ControlStyles.ResizeRedraw, True)
        Me.DrawMode = DrawMode.OwnerDrawFixed

        Me.m_ControlBuffer = New Bitmap(Me.Width, Me.Height)
        Me.m_ControlGraphics = Graphics.FromImage(m_ControlBuffer)
        Me.m_BackBuffer = New Bitmap(Me.Width, Me.Height)
        Me.m_BackGraphics = Graphics.FromImage(m_BackBuffer)

        Dim backcolor As Color = If(Enabled, m_UITheme.TextBoxColor, Color.White)
        BackgroundBrush = New SolidBrush(backcolor)
    End Sub

and this the function i call on my paint method

Public Sub CustomPaint(screenGraphics As Graphics)
        ' If there is body to be drawn.
        If Me.Width > 0 AndAlso Me.Height > 0 Then
            ' Clear the background image graphics 
            If Me.m_backImage Is Nothing Then
                '	Cached Background Image
                Me.m_backImage = New Bitmap(Me.Width, Me.Height)
                Dim backGraphics As Graphics = Graphics.FromImage(Me.m_backImage)
                backGraphics.Clear(Color.Transparent)
                Me.PaintTransparentBackground(backGraphics, Me.ClientRectangle)
            End If

            m_BackGraphics.Clear(Color.Transparent)
            m_BackGraphics.DrawImageUnscaled(Me.m_backImage, 0, 0)

            m_ControlGraphics.Clear(Color.Transparent)
            m_ControlGraphics.SmoothingMode = SmoothingMode.HighQuality

            ' Begin drawing
            Dim path As GraphicsPath = GetBoxBorder()
            m_ControlGraphics.FillPath(BackgroundBrush, path)

            PaintArrowAndLine(m_ControlGraphics)

            ' Draw text
            DrawText(m_ControlGraphics)

            m_ControlGraphics.Flush()

            m_BackGraphics.DrawImage(m_ControlBuffer,
                                         New Rectangle(0, 0,
                                                       m_ControlBuffer.Width,
                                                       m_ControlBuffer.Height),
                                         0, 0,
                                         m_ControlBuffer.Width,
                                         m_ControlBuffer.Height,
                                         GraphicsUnit.Pixel)
            m_BackGraphics.Flush()

            '	Now paint this to the screen
            screenGraphics.DrawImageUnscaled(m_BackBuffer, 0, 0)
        End If
    End Sub

Thanks in advance