Having problem scrolling using SetScrollInfo API

Hello everyone!
I'm working on a new application and I use the SetScrollInfo and GetScrollInfo Api's and I'm having some problems:

1. I'm able to scroll my own textbox control on my form but I can only see the scrollbar being updated and not the text inside the textbox control moving I'm using this code:

Code:

---

        Dim si As New SCROLLINFO()
        si.cbSize = Marshal.SizeOf(si)
        si.nPos = ScrollValue
        si.fMask = ScrollInfoMask.SIF_POS
        SetScrollInfo(Handle, ScrollBar, si, True)

---

2. The GetScrollInfo and SetScrollInfo Api's doesn't work in other applications and in windows like Firefox and Windows Explorer. I use the GetFocus Api to get the handle but still it doesn't seem to work (nothing happens) I got a dll error saying that the window handle is invalid, I tried both GetFocus and GetForegroundWindow Api's to get the handle, any ideas?

Thank you!

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