Changing the height of a row is very slow
 

Hi,

On some computers, changing the height of a row in a given document is
very slow (about 2 seconds), on other computers with the same document
it is almost immediate. I haven't notice any difference between these
computers. The strange thing is that a few months ago, changing the
height of a row was immediate on every machines.
This slow down is critical, because i use the changing of the height in
a macro that takes 2 minutes more to run on the slow computers, while
it takes only 5 s on the fast computers.
I can reinstall Office, but i prefer to know what's wrong in the
installation or in the document. I would avoid to reinstall Office
every few months if the slow down appears again.

Thanks in advance for any help or suggestion.

Regards,
Marc