the How do you set thumb proportion of a scrollbar? It doesn't work properly
in Excel. I tried finding the handle to the control with an API 'GetWindow'
call (and some others) but Excel seems to hide the control (I can find
slider handles but not anything other than system scrollbars. The LargeChange
value won't set it properly (won't go past 50%) and it sets the thumb size in
a very nonlinear way. I'm using Excel 2002.