This is about the options list on the Modules tab. Currently you have Consumables on top, followed by Mech, with Weapons at the bottom. Alphabetical.
Meanwhile on the mech itself, Mech comes first, followed by Weapon, with the Mech/Weapon next, and Consumables last.
How about rearranging the lists so they map to where you plan to drag and drop the item?
![Posted Image](http://puu.sh/jvgNx/f4447dd732.jpg)