We have sort and stack buttons. We need one more that takes and stores all the contents in the chest. Good?
It sounds great but when you consider competitive looting, it causes a problem. Like me and you kill a guy and we are both trying to loot at the same time. Or we both clicked on the same chest and are both trying to loot it. I believe that is why this doesn't exist. I suppose they could add it and it is just greyed out in competitive looting situations but yeah, I think that's why we don't already have it.