Hi Andrey,Firstly, Sorry for the inconvenience,The "Resize" button works exactly as you described. However, there is a known bug that, if the puzzle was rotated by the author, then the resize button creates an issue. It's a work in progress but might take time to get fixed as I am currently traveling.Can you please let me know which puzzle? So that I make sure, it's because of that reason and not something else.On your second note, how to reset it, This is because penpa_PLUS_ has the feature to save your progress, unfortunately, the grid is now corrupted because of the bug and it got saved that way, follow the below steps to reset it)After you load the puzzle -> Click on the Settings on the Top Right --> Click on "Clear this puzzle" (Located at the bottom of the popup), Set Local Storage --> OFF and then reload the page. It should reset your puzzle back to its original.Let me know if you still face any issues,Thank you.