RichTextBox - Scroll vs. page issue

Hello all.

I made this great property that (seems) to work as expected:

Code:

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    <Browsable(False), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)> _
    Public Property ScrollPosition() As Point
        Get
            SendMessage(Me.Handle, EM_GETSCROLLPOS, 0, ScrollPosition)
        End Get
        Set(ByVal value As Point)
            SendMessage(Me.Handle, EM_SETSCROLLPOS, 0, value)
        End Set
    End Property

---

But when I need to scroll the vertical bar to a value higher than 65536 it starts to behave the wrong way. For example, this causes the control to jump up:

Code:

---

ScrollPosition = ScrollPosition

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EDIT

http://www.vbmonster.com/Uwe/Forum.a...ling-incorrect
But how to convert it to work with my code...

Code:

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    Private Function CorrectScrollPosY(ByVal Index As Long, ByVal lngNewScrollPos As Long) As Long
        If (lngPixelCntY(Index) > 65535) Then
            CorrectScrollPosY = CLng(CDbl(lngNewScrollPos) * lngLineHeightPixels * rtbDiff(Index).LineCount / 65535.0#)
        Else
            CorrectScrollPosY = lngNewScrollPos
        End If
    End Function

---

Plus I can't scroll to a line; it must scroll by pixel. (to prevent a strange shaking when typing)

EDIT

Ok discovered the point structure contains two UShort values, not two integers at all! :o
I'll see if a custom structure works out. < Does not work out; same issue; system uses two UShorts :/

Thought of using the SCROLLINFO structure, but that API doesn't update the control...
OK I'm out of luck here. Any help greatly appreciated.