Thanks for your reply, it's beginning to make a bit more sense now. However, I believe there is still a gremlin lurking somewhere in the woodpile. 

I response to your question regarding programmatic vs declarative creation of the controls - I've tried both. I started with declarative and encountered the problem with the second grid on the page losing its formatting on a postback. So, i though I'd try programming - it does a little better (for example some issues with styles are circumvented) but the second grid still loses its formatting on postback.

So, it still looks like a bug such that when two (or more?) grids are on the same page the second loses its viewstate on postback.

I hate having to requery the database to get round a bug like this, but at least I know what to do. (I have to requery the database because although the grid data may remain unaltered, all my grid formats: fonts, colour, border properties and so forth are stored in tables.).

Thanks again.

In that case what you can do is to store all the data you want in the session object. That way you can reconfigure your grids on every postback without having to requery the database. There might be a better solution, but this one is quick and effective :)