Cases, like a small protector case should go into hands and open those slots for quicker use.
I don't if there is supposed to be a better way, but how I open cases is by dragging them out of my inventory and into the vicinity to open them. There is a better way, like putting the box into Hands so that you can open the case and search it without dragging it around. I feel that dragging the object around multiple zones could cause issues like accidental object deletions. {F28396}