[Troubled_by_utra_rapid_mouse]

I'm using Office 2007 and an HP mouse under Windows 7.

From time to time, apparently at random (although perhaps there is some
keyboard of scroll wheel trigger I have not identified), the mouse cursor
changes from the normal pointer to a black-filled triangle above or below a
central dot, and mouse scrolling becomes ultra-ultra-fast, and bypasses the
scroll wheel. The slightest movement of the mouse up or down quickly makes
the Word document, Excell workbook, or whatever, jump to the top or bottom of
the open file. This "black-filled triangle above/below a central dot"
corresponds to nothing in the HP mouse cursor configuration images, so I'm
assuming that Word or Windows 7 is somehow doing this. No mouse setting in
control panel seems to correspond to this annoying feature.

This annoying function scrolls without use of the normal scroll wheel. That
is to say, suddenly scrolling occurs simply by moving the mouse slightly
upward or downward.

Has anybody seen this troublesome feature? Is there anyway to stop it?

It is entirely unclear to me if this is something due to the HP mouse
software, an annoying feature of Office 2007, or something in Windows 7.