F2 will put the cursor in "edit" mode (rather than insert/point-to mode).
You can then use arrow keys to move around safely.

HTH,

"Rich" wrote in message
...
If a very large formula is required for a named range, how does one go
about
editing it on the Define Name dialogue?

I've been writing the formula in notepad, then pasting the whole thing
into
the text box. Every time I try to move the cursor along in the text box
with
the arrow keys, Excel thinks I am tying to add data to the formula when
all I
really want to do is see the parts of the formula beyond the edge of the
text
box. The Define Name panel cannot be sized to allow the whole formula to
be
seen.

Thanks for any help.