Insert key works in Norton Commander interface unless you have "explorer style selection" switch on (it is off by default).
now for non continuous file selection using keyboard,
we can
1. hold control key
2. move up or down using arrow key
3. use space bar to select/unselect
Can we add insert key also as a key to do select/unselect. It is easier to move hands between ins key and arrow keys than between space bar and arrow keys
This is a low priority request. So dont bother if it is difficult