Just replied to something that vanished 
still worth a check
The grid on a per-image basis is set up in Image -> Configure Grid set the spacing to 1 for both width and height. screenshot. https://i.imgur.com/lBA9AQt.jpg
The grid visibility is toggled on/off in View -> Show Grid https://i.imgur.com/4cZ16df.jpg
and a hint, For single pixel painting, which you will probably need, use the pencil tool which does not create anti-aliasing and a brush size of 1. There is a small hard brush in there somewhere 'pixel (3x3)'
still worth a checkThe grid on a per-image basis is set up in Image -> Configure Grid set the spacing to 1 for both width and height. screenshot. https://i.imgur.com/lBA9AQt.jpg
The grid visibility is toggled on/off in View -> Show Grid https://i.imgur.com/4cZ16df.jpg
and a hint, For single pixel painting, which you will probably need, use the pencil tool which does not create anti-aliasing and a brush size of 1. There is a small hard brush in there somewhere 'pixel (3x3)'