A tool that highlights 2-candidate cells would be pretty useful, in my opinion, for finding possible naked pairs and XY-wings.
Just a thought.
sudocue idea: highlight 2-candidate cells
I concur. The 2-candidate cell highlighter was always one of my favorite tools in Simple Sudoku. I miss the feature since I've converted over to SudoCue (I held out for a while, but SudoCue has overtaken SS as the best solver available).
"Obviousness is always the enemy to correctness."-Bertrand Russell