I'm trying to expand an APFS Container but it won't let me (10.14.6). What I want to do is to grow the 150GB container to 400GB at the expense of the largest 'SSD Data' container. However, when I shrink the 'SSD Data' container by 250GB, it automatically creates a new container, the 'Untitled' that you see in the image, instead of creating free space. Why is that? I want the 250GB to become free space so that I can expand the 150GB container with it.
