Thank you for your reply.
I know exactly the objective of crosswords.
But because we use it with Latin definitions for French people, the future players will need a bit of help.
I implemented a “dirty” solution and managed to add what I wanted.
Here you are a screenshots of the current implementation.
When the payer click on the “Show the solution” button, it get an alert message to confirm if he want really show the solution (1st click only). If yes, the solution is displayed on the grid with a 10s countdown timer (orange vertical line on top of the grid).
Again it ‘s not a very clean programming, but that works!
I have also translated your plugin in French and I’ve noticed that the buttons labels are not present in the translation file : ymc-button-reload, ymc-button-reset, ymc-button-start, ymc-button-pause.