Sorted containers sort items in stacks by quality.

Unsorted containers average item quality into one stack. If you add items of low quality the quality of the stack goes down. If you add items of high quality the quality of the stack goes up.

If you toggle sorted/unsorted it only affects new items being added to the container, not existing items already in the container.

There is a bug where sometimes a container set as sorted will act like an unsorted container. The only fix is to use another container.