Extreme Care Needed to Use this App – Big Bad Sudoku Book Review

Re iPad version: 1. Notes keypad is way too small for normal sized fingers. Also too close to primary keypad. 2. The three icons below notes keypad are too close. Too easy to hit accidentally. 3. The X button does not always restore notes properly after deletion. This has to be a foolproof undo button. EDIT: This is a critical bug that makes a real mess if you make a mistake because it does not restore notes properly after using the X button. Notes in OTHER CELLS are not restored. 4. No way to highlight all single note numbers. E.g., all candidate 3s. 5. Incorrect selections should be flagged immediately. (Optionally, of course.)
Review by jch1939 on Big Bad Sudoku Book.