I often use a separate game for planning, so that players don't see my rolls'n'stuff by accident.
Sometimes I even do a test-run as a pickup game.
...and then I import them to the actual game.
The problem is that the Transmogrifier does not import the characters along with the map, so I end up having to import these separately, associating them with the right token ....
Would it be possible to get a pop-up alert like:
******************************************************
This map contains characters that doesn't exist in the game you are transferring it to.
Would you like to import these characters as well?
YES/NO
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One problem is that I don't always realise that one character is missing, until days later.
When I do, it can be tricky to remember which game I used for creating that character, so that I can go back and fix the problem.