Switch. Show - hide coordinates ruler for the current active board window.
Switch. Show - hide letters which points out possible next moves for fuseki/joseki.
Switch. Show - hide all possible symmetrical position for the letters
which points out possible next moves for fuseki/joseki.
If pressed then letters for fuseki/joseki next move colored depends
on strength of strongest player made this move:
red - professional player,
green -semiprofessional player,
navy (dark blue) - strong amateur player.
Filter. Show/hide visible of letters pointed for small number of
games for current position.