I have only been using Multi Commander a short time. Initially, I did not change anything, and the column dimension was always there. At first, I just ignored it but then decided to start customizing. Simple solution was to delete column and save current layout, which was the default. When that didn't work, I created my own profile without the size or dimension columns. When I launched Multi Commander the next time, both came back.
This should not be this difficult, so I started reading about saving configurations. I recall reading about bugs and issues which is why I posted now. I typically know what I am doing.