Cant pickup weapons on the ground

[The Map]

Whenever a unit with a weapon such as an MG dies, I am unable to send another unit to pick it up. I can check the inventory of the dead unit, but the gun will be laying on the ground and not part of the inventory. I can not examine the gun either. How can I pick it up?

[Kabbitkavro]

You have to hold C and highlight it, then right click it directly