Hi Martin!
AFAIK this can't be done.
The ToolTip default can be changed but I think you'll find the comment
indicator can't and you'll have to wait and see if this is an earth
shattering enhancement to the next version of Excel.
--
Regards
Norman Harker MVP (Excel)
Sydney, Australia
(e-mail address removed)
Excel and Word Function Lists (Classifications, Syntax and Arguments)
available free to good homes.