I discovered a small bug. If you remove a container without removing it from the folder, it still shows up as in the folder count, but there is no way to remove it. As seen here:
It says there are 1/2 containers started, but there is only 1 container left in the folder. In the folder.json file, the old container (linuxgsm-docker) is still listed as a member of the folder. If you click on the folder, the old container doesn't show up, and there isn't any way to remove the container (besides editing the /boot/config/plugins/docker.folder/folder.json file directly).
As I said, I can remove the extra container by modifying the file, so it's a minor issues, but I thought I'd post it here in case anyone else has this same issue.