You said it "doesn't happen on all documents"... does that mean it
**always** happens on specific documents (that is, is it repeatable), or is
it a haphazard sort of thing?

Rick

Thanks for your reply.

Hmm, it does appear to be more haphazard than I thought it was.
Closing and restarting Excel seemed to do the trick, and now the
single-clicks work the way the should. But this has happened before,
so I wonder if it's some kind of rare bug that only some users
experience. (Or, could it be actually related to the mouse--I have
Logitech MX518--and not the application? Still, my pointing device
works perfectly as far as I can tell.)

Regardless, I'll try to give a more thorough description of what
happened, if only to give this thread a better sense of closure.

In the Excel file where this happened, I have 12 tabs with one
spreadsheet each (one for each month of the year), and one additional
tab at the end with data I use for the previous sheets (names of
people in a named range for drop-down selects). In the first worksheet
and the final, data sheet, single-clicks worked the way they should,
but not on the other 11 worksheets--where one click would select
multiple cells.

I eventually noticed that when I single-clicked a cell, the following
expression appeared in the Name Box (the box to the left of the
Formula Bar): 5R x 1C. Normally, an expression like that would only
appear WHEN you are click-dragging the mouse to select multiple cells.
Otherwise, only the name of the cell you click appears there, or the
name of any Named Range you have defined. However the glitch was
obviously behaving as if I were click-dragging the mouse, making Excel
automatically grab those cells below.

I Googled or a while and couldn't find any mention of this trouble, so
it looks like the OP and I are the only ones in the known universe
with this experience :-P.

Oh well, it seems to be gone for the time being...