Had to change use of the middle mouse button as this is used when you press
the mouse wheel.
Winding the mouse wheel will scroll the page up or down one line.
(SB_LINEUP, SB_LINEDOWN).
Press the mouse wheel and then moving the mouse up or down lets you scroll
through the whole document.
I have only tested this on Win98. It needs to be tested on Win95 and WinNT
as these don't have built in messages for Mouse Wheel support and use a
registered message instead.
Files:
ap_Win32Frame.cpp
ap_Win32Frame.h
xap_Win32Frame.cpp
xap_Win32Frame.h
