We have HERE...
http://www.eq2interface.com/download...fo.php?id=3448
...a mod to show all 9 trade slots in the window.
You can trade up to 9 items (each way) at a time with or without modding the window, but the problem is that confusion is generated when someone without the mod is on the receiving end. The chat window notification of items added doesn't even include a link to the item.
So, for this reason, we request that all 18 slots be visible in the default interface.