The docker toolbox environment variable adds a port container and everything in it is gone?

  docker, question

I have just started to learn to use docker.
A normal container
I’m in a meal operation
Then I added a 3306 port and saved it
I don’t know what the situation is.
How do I save the changes I made

In other words, how to add a port mapping to an existing container

All right, after several days of exploration, I seem to understand a little bit.
Port mapping seems to be specified only in the docker create phase or with dockerfile.
I don’t know how kitematic is realized.
One solution is to use docker commit to turn a container commit into a new mirror image
This new image is used to run a new container and specify a new port mapping at the same time.