Simple QoL suggestion to let us add items to containers the same way we can add them to stockpiles:
Have an item on the cursor, shift+RMB to move this into the container clicked onto (if inventory space in it is available) same as adding fuel to lightable.
Preferably this plus shift+alt+RMB (or another sane key modifyer combination) which would move all of that kind.
This would complement the ability to shift+RMB to pull stuff from a container without the need to open it, which should be changed to shift+RMB pulling one and shift+alt+RMB pulling a full inventory.