When you edit an order, like adding a product, several parts of the order screen gets refreshed by ajax if you have it enabled. Like the products table, total pane, etc.
The admin comments, however, does not, and you might miss important information like stock decrement and such.
To reproduce simply have the stock module enable and active on a product, once you add it to a newly admin created order, you see the product added and total updated but nothing on admin comments. However, if you click on "edit" to reload the page, you'll see the comments there.
Comments
Comment #1
hanoiiAttached is the patch that solves this.
Comment #2
hanoiiOoops
Comment #3
longwaveCommitted, thanks for the patch (and separate issue!). I don't consider this a bug though - just a nice feature :)