It is a common problem. See:

http://word.mvps.org/FAQs/Formatting...eformatted.htm

--
Greg Maxey/Word MVP
A Peer in Peer to Peer Support

Alan Jones wrote:
When I highlight one paragraph to change the format, ie. bold it, left
justify, move to the right/left, etc.

The change gets applied to every paragraph through out the document.
Now I suppose it made the change to all paragraphs of the same style.

I am sure there must be a flag to say either apply to the entire
style or just the highlighted text but I can't find it.