...
The user can lock any column in the Selected Columns list by clicking the pin icon, which is shown on hover. In this case:
the icon toggles from idle to selected.
the item moves to the top of the list.
the item can be ordered only inside the group of locked items.
within the Data Table, locked columns are anchored to the left. Locked items can be reordered only inside the group of locked items.
The user can unlock the column by clicking the pin icon again.
  |
Saving changes
...