#273 No UNDO button and hidden rectangle problem

[Gordon]

Hello. V2.2.0 (I cant seem toi change version number on this bug thing. )

Im playing UNFAIR 1644. but found a bug.

Row 1, column 2 is a 5 or 6. Row 1 Column 3 is a 5 or 6.

Row 8 Column 2 & 3 is a 5 or 6, and R8, C 3 is alsoa 5 or 6 (hidden rectangle).

Now - if a 6 HAS to be in row1 column 2 or 3, a 6 CANNOT be in row1 column 4.,

if a 6 HAS to be in row 1 3, and Row 8 column 3. a 6 CANNOT be in row 5 column 3.,

However - If i remove these two 6's (row 1 col 4 and Row 5 col 3) - i get an error where NEXT HINT says the puzzle camnnot be solved.

BUG 1 :- The fact that removing the 6's from the boxes that cannot be a 6 - produces an unsolvable board.

BUG 2 :- There needs to be an UNDO button - To remember (backwards) the boxes you removed

in V 2.2.0 - There is no undo button. (i'll download the latest version soon)..

[CCV]

"Now - if a 6 HAS to be in row1 column 2 or 3, a 6 CANNOT be in row1 column 4.", is wrong. One of them has to be 5, yes. There's possibity for 1 in r1c3 and plenty of other places for 6 in block 1 and colums 2&3.

If you use "Alternate mouse mode" (Preferences > General), or go to Active cell view, then you can easily toggle candidates back on. If removing any candidate invalidates the puzzle, then Progress marker changes to red with an X mark.

Btw, 2.2.0 is the latest official release and it does have Undo anyway.

[Gordon]

Thanks - alternate mouse mode