Custom Amounts in Trading

[MOOcow]

Currently ammo is the only item that asks for an amount when in the trade menu, while all shops show the number chooser for every item.

If you don't want a custom amount for each item, could you make it so if you shift-click on the add button, it asks for a custom amount.

It takes forever to click the add button 100+ times.

[kronik]

This definitely has to be done. Doesn't have to be exactly like this but something similar following the same idea.