In AppCell.vue file(mouseMove function) - have to be change specific size to tileSize. I leave this way, because I don't wanna mess up your code, from toolbox tileSize is undefined. Toolbox component is missing a prop with tileSize. Beside that everything work well. I did not interfere with your code I just adapt to your logic. Have a nice day! :)
In AppCell.vue file(mouseMove function) - have to be change specific size to tileSize. I leave this way, because I don't wanna mess up your code, from toolbox tileSize is undefined. Toolbox component is missing a prop with tileSize. Beside that everything work well. I did not interfere with your code I just adapt to your logic. Have a nice day! :)