Mon, 27 Jul 2020 12:08:23 +0200
fix: window cannot get smaller than the field
| 7 | 1 | _ 1 _ 9 _ _ 8 _ _ |
| 2 | _ _ _ _ _ 8 _ _ 4 | |
| 3 | 6 _ 5 _ _ _ 7 _ _ | |
| 4 | _ 9 _ _ 6 _ _ _ 8 | |
| 5 | _ _ _ 2 _ 7 _ _ _ | |
| 6 | 8 _ _ _ 3 _ _ 6 _ | |
| 7 | _ _ 2 _ _ _ 5 _ 3 | |
| 8 | 1 _ _ 4 _ _ _ _ _ | |
| 9 | _ _ 6 _ _ 2 _ 1 _ |