The user should be able to set the contents of a cell to 'generic ship segment', and at some later point change it to a specific ship segment. But currently whenever you put anything in a cell, you can never change it to anything else at any later point.
The user should be able to set the contents of a cell to 'generic ship segment', and at some later point change it to a specific ship segment. But currently whenever you put anything in a cell, you can never change it to anything else at any later point.