What makes the 'loading' box appear when adding a product

[Robbie@FireFold]

Quick question on why/what makes the loading box appear in the middle of the page. When adding products I have found that some products take much longer then others. I can do Product A - which is instant - then try Product B and get a 1-2 second delay.

These delays are internal - so I'm a little scared that external might have an even longer delay. Though this might just be an Ajax feature - which I assume would be locally based?

Thanks in advance!

[mazhar]

Yes this is locally based Ajax feature