[Bug 48770] New: wine-mono doesn't scroll large textboxes correctly

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=48770

Bug ID: 48770
           Summary: wine-mono doesn't scroll large textboxes correctly
           Product: Wine
           Version: 5.4
          Hardware: x86
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: mscoree
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

This is AFAICT a mono bug, yet as I recall the policy here is to patch
wine-mono in such cases.

So, if a textbox is larger than Int16, you *can* scroll past that point using
keyboard, but if instead you try to use the scrollbar, it overflows and resets
to position to the beginning.

Quite likely this is caused by
https://github.com/mono/mono/blob/master/mcs/class/System.Windows.Forms/Syst...

I've tried to see how it's done in dotnet/winforms, but there's no equivalent
for TextBoxTextRenderer there. If some limit is imposed, it doesn't seem to be
done in GDI/TextRenderer.cs. Only thing that seems relevant would be 
GDI/WindowsGraphics2.cs, but there the limits are Int32.