When I double-click, it quickly takes the item then releases it in the loot section.
The inventory doesn't create new rows when the last item is occupied, so that leaves only one option to loot, one has to LOOT ALL, then drop unwanted items. It would be more convenient to be able to simply click on items to loot, or optionally, to drag them to directly place them somewhere specific, like another character's inventory or to equip it. EDIT: it's actually the same problem to put an equiped item in the inventory, if all rows are occupied, it's not possible.
Items tend to be automatically equiped too, which may not be the desired action. It's less confusing to drop everything in the inventory and let the player equip any item manually.